diff --git a/projects/observability/src/pages/explorer/explorer.component.test.ts b/projects/observability/src/pages/explorer/explorer.component.test.ts
index a77f92535..617e82718 100644
--- a/projects/observability/src/pages/explorer/explorer.component.test.ts
+++ b/projects/observability/src/pages/explorer/explorer.component.test.ts
@@ -360,7 +360,7 @@ describe('Explorer component', () => {
     spectator.query(ExploreQueryEditorComponent)!.setInterval(new TimeDuration(30, TimeUnit.Second));
     spectator.query(ExploreQueryEditorComponent)!.updateGroupByKey(
       {
-        keys: ['apiName'],
+        keyExpressions: [{ key: 'apiName' }],
         limit: 6,
         includeRest: true
       },
@@ -370,7 +370,7 @@ describe('Explorer component', () => {
     expect(queryParamChangeSpy).toHaveBeenLastCalledWith({
       scope: 'spans',
       series: ['column:avg(second)'],
-      group: 'apiName',
+      group: ['apiName'],
       limit: 6,
       other: true,
       interval: '30s'
diff --git a/projects/observability/src/pages/explorer/explorer.component.ts b/projects/observability/src/pages/explorer/explorer.component.ts
index 185d1a348..9a379decc 100644
--- a/projects/observability/src/pages/explorer/explorer.component.ts
+++ b/projects/observability/src/pages/explorer/explorer.component.ts
@@ -9,7 +9,7 @@ import {
   TimeDurationService
 } from '@hypertrace/common';
 import { Filter, ToggleItem } from '@hypertrace/components';
-import { isNil } from 'lodash-es';
+import { isEmpty, isNil } from 'lodash-es';
 import { concat, EMPTY, Observable, Subject } from 'rxjs';
 import { map, take } from 'rxjs/operators';
 import { CartesianSeriesVisualizationType } from '../../shared/components/cartesian/chart';
@@ -19,6 +19,7 @@ import {
   ExploreVisualizationRequest
 } from '../../shared/components/explore-query-editor/explore-visualization-builder';
 import { IntervalValue } from '../../shared/components/interval-select/interval-select.component';
+import { AttributeExpression } from '../../shared/graphql/model/attribute/attribute-expression';
 import { AttributeMetadata } from '../../shared/graphql/model/metadata/attribute-metadata';
 import { MetricAggregationType } from '../../shared/graphql/model/metrics/metric-aggregation';
 import { GraphQlGroupBy } from '../../shared/graphql/model/schema/groupby/graphql-group-by';
@@ -216,8 +217,8 @@ export class ExplorerComponent {
   }
 
   private getGroupByQueryParams(groupBy?: GraphQlGroupBy): QueryParamObject {
-    const key = groupBy?.keys[0];
-    if (key === undefined) {
+    const keyExpressions = groupBy?.keyExpressions ?? [];
+    if (keyExpressions.length === 0) {
       return {
         // Clear existing selection
         [ExplorerQueryParam.Group]: undefined,
@@ -227,7 +228,7 @@ export class ExplorerComponent {
     }
 
     return {
-      [ExplorerQueryParam.Group]: key,
+      [ExplorerQueryParam.Group]: keyExpressions.map(expression => this.encodeAttributeExpression(expression)),
       [ExplorerQueryParam.OtherGroup]: groupBy?.includeRest || undefined, // No param needed for false
       [ExplorerQueryParam.GroupLimit]: groupBy?.limit
     };
@@ -238,7 +239,9 @@ export class ExplorerComponent {
       contextToggle: this.getOrDefaultContextItemFromQueryParam(param.get(ExplorerQueryParam.Scope) as ScopeQueryParam),
       groupBy: param.has(ExplorerQueryParam.Group)
         ? {
-            keys: param.getAll(ExplorerQueryParam.Group),
+            keyExpressions: param
+              .getAll(ExplorerQueryParam.Group)
+              .flatMap(expressionString => this.tryDecodeAttributeExpression(expressionString)),
             includeRest: param.get(ExplorerQueryParam.OtherGroup) === 'true',
             // tslint:disable-next-line: strict-boolean-expressions
             limit: parseInt(param.get(ExplorerQueryParam.GroupLimit)!) || 5
@@ -294,6 +297,19 @@ export class ExplorerComponent {
       }
     ];
   }
+
+  private encodeAttributeExpression(attributeExpression: AttributeExpression): string {
+    if (isEmpty(attributeExpression.subpath)) {
+      return attributeExpression.key;
+    }
+
+    return `${attributeExpression.key}__${attributeExpression.subpath}`;
+  }
+  private tryDecodeAttributeExpression(expressionString: string): [AttributeExpression] | [] {
+    const [key, subpath] = expressionString.split('__');
+
+    return [{ key: key, ...(isEmpty(subpath) ? { subpath: subpath } : {}) }];
+  }
 }
 interface ContextToggleItem extends ToggleItem<ExplorerContextScope> {
   value: ExplorerContextScope;
diff --git a/projects/observability/src/public-api.ts b/projects/observability/src/public-api.ts
index 030e8fbe9..634484dbb 100644
--- a/projects/observability/src/public-api.ts
+++ b/projects/observability/src/public-api.ts
@@ -64,6 +64,7 @@ export * from './shared/services/metadata/metadata.service';
 export * from './shared/services/metadata/metadata.service.module';
 export * from './shared/graphql/model/metadata/attribute-metadata';
 
+export * from './shared/graphql/model/attribute/attribute-expression';
 export * from './shared/graphql/model/metrics/metric-aggregation';
 export * from './shared/graphql/model/metrics/metric-health';
 
diff --git a/projects/observability/src/shared/components/explore-query-editor/explore-query-editor.component.test.ts b/projects/observability/src/shared/components/explore-query-editor/explore-query-editor.component.test.ts
index 984ed8188..3b63a3e12 100644
--- a/projects/observability/src/shared/components/explore-query-editor/explore-query-editor.component.test.ts
+++ b/projects/observability/src/shared/components/explore-query-editor/explore-query-editor.component.test.ts
@@ -176,7 +176,7 @@ describe('Explore query editor', () => {
       expect.objectContaining({
         series: [defaultSeries],
         groupBy: {
-          keys: ['first groupable'],
+          keyExpressions: [{ key: 'first groupable' }],
           limit: 5 // Default group by limit
         }
       })
@@ -215,7 +215,7 @@ describe('Explore query editor', () => {
       expect.objectContaining({
         series: [defaultSeries],
         groupBy: {
-          keys: ['first groupable'],
+          keyExpressions: [{ key: 'first groupable' }],
           limit: 6
         }
       })
diff --git a/projects/observability/src/shared/components/explore-query-editor/explore-query-editor.component.ts b/projects/observability/src/shared/components/explore-query-editor/explore-query-editor.component.ts
index cca51a6fd..0a2a1b99d 100644
--- a/projects/observability/src/shared/components/explore-query-editor/explore-query-editor.component.ts
+++ b/projects/observability/src/shared/components/explore-query-editor/explore-query-editor.component.ts
@@ -39,7 +39,7 @@ import {
         <ht-explore-query-group-by-editor
           class="group-by"
           [context]="currentVisualization.context"
-          [groupByKey]="(currentVisualization.groupBy?.keys)[0]"
+          [groupByKey]="(currentVisualization.groupBy?.keyExpressions)?.[0]?.key"
           (groupByKeyChange)="this.updateGroupByKey(currentVisualization.groupBy, $event)"
         ></ht-explore-query-group-by-editor>
 
@@ -103,8 +103,8 @@ export class ExploreQueryEditorComponent implements OnChanges, OnInit {
       this.setInterval(this.interval);
     }
 
-    if (changeObject.groupBy && this.groupBy?.keys.length) {
-      this.updateGroupByKey(this.groupBy, this.groupBy.keys[0]);
+    if (changeObject.groupBy && this.groupBy?.keyExpressions.length) {
+      this.updateGroupByKey(this.groupBy, this.groupBy.keyExpressions[0]?.key);
     }
   }
 
@@ -117,7 +117,9 @@ export class ExploreQueryEditorComponent implements OnChanges, OnInit {
       this.visualizationBuilder.groupBy();
     } else {
       this.visualizationBuilder.groupBy(
-        groupBy ? { ...groupBy, keys: [key] } : { keys: [key], limit: ExploreQueryEditorComponent.DEFAULT_GROUP_LIMIT }
+        groupBy
+          ? { ...groupBy, keyExpressions: [{ key: key }] }
+          : { keyExpressions: [{ key: key }], limit: ExploreQueryEditorComponent.DEFAULT_GROUP_LIMIT }
       );
     }
   }
diff --git a/projects/observability/src/shared/components/explore-query-editor/explore-visualization-builder.test.ts b/projects/observability/src/shared/components/explore-query-editor/explore-visualization-builder.test.ts
index f71afa668..d46c5bd84 100644
--- a/projects/observability/src/shared/components/explore-query-editor/explore-visualization-builder.test.ts
+++ b/projects/observability/src/shared/components/explore-query-editor/explore-visualization-builder.test.ts
@@ -84,7 +84,7 @@ describe('Explore visualization builder', () => {
       spectator.service
         .setSeries([buildSeries('test1')])
         .groupBy({
-          keys: ['testGroupBy'],
+          keyExpressions: [{ key: 'testGroupBy' }],
           limit: 15
         })
         .setSeries([buildSeries('test2')]);
@@ -92,7 +92,7 @@ describe('Explore visualization builder', () => {
       expectObservable(recordedRequests).toBe('10ms x', {
         x: expectedQuery({
           series: [matchSeriesWithName('test2')],
-          groupBy: { keys: ['testGroupBy'], limit: 15 }
+          groupBy: { keyExpressions: [{ key: 'testGroupBy' }], limit: 15 }
         })
       });
     });
diff --git a/projects/observability/src/shared/dashboard/dashboard-wrapper/navigable-dashboard.component.test.ts b/projects/observability/src/shared/dashboard/dashboard-wrapper/navigable-dashboard.component.test.ts
index beb17daaa..a80fd0f27 100644
--- a/projects/observability/src/shared/dashboard/dashboard-wrapper/navigable-dashboard.component.test.ts
+++ b/projects/observability/src/shared/dashboard/dashboard-wrapper/navigable-dashboard.component.test.ts
@@ -144,7 +144,7 @@ describe('Navigable dashboard component', () => {
     };
     spectator.query(FilterBarComponent)?.filtersChange.next([explicitFilter]);
     expect(mockDataSource.addFilters).toHaveBeenCalledWith(
-      expect.objectContaining({ key: 'foo', operator: GraphQlOperatorType.Equals, value: 'bar' })
+      expect.objectContaining({ keyOrExpression: 'foo', operator: GraphQlOperatorType.Equals, value: 'bar' })
     );
   });
 
diff --git a/projects/observability/src/shared/dashboard/data/graphql/explore/explore-cartesian-data-source.model.test.ts b/projects/observability/src/shared/dashboard/data/graphql/explore/explore-cartesian-data-source.model.test.ts
index b901b1ba7..55d4195be 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/explore/explore-cartesian-data-source.model.test.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/explore/explore-cartesian-data-source.model.test.ts
@@ -155,7 +155,7 @@ describe('Explore cartesian data source model', () => {
     ];
 
     model.groupBy = {
-      keys: ['baz'],
+      keyExpressions: [{ key: 'baz' }],
       includeRest: true,
       limit: 5
     };
@@ -220,7 +220,7 @@ describe('Explore cartesian data source model', () => {
     ];
 
     model.groupBy = {
-      keys: ['baz'],
+      keyExpressions: [{ key: 'baz' }],
       limit: 5
     };
 
diff --git a/projects/observability/src/shared/dashboard/data/graphql/explore/explore-cartesian-data-source.model.ts b/projects/observability/src/shared/dashboard/data/graphql/explore/explore-cartesian-data-source.model.ts
index 27fa2e81e..092bcd828 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/explore/explore-cartesian-data-source.model.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/explore/explore-cartesian-data-source.model.ts
@@ -5,6 +5,7 @@ import { NEVER, Observable, of } from 'rxjs';
 import { map, mergeMap } from 'rxjs/operators';
 import { Series } from '../../../../components/cartesian/chart';
 import { ExploreRequestState } from '../../../../components/explore-query-editor/explore-visualization-builder';
+import { AttributeExpression } from '../../../../graphql/model/attribute/attribute-expression';
 import { MetricTimeseriesInterval } from '../../../../graphql/model/metric/metric-timeseries';
 import { GraphQlFilter } from '../../../../graphql/model/schema/filter/graphql-filter';
 import { ExploreSpecification } from '../../../../graphql/model/schema/specifications/explore-specification';
@@ -107,19 +108,19 @@ export abstract class ExploreCartesianDataSourceModel extends GraphQlDataSourceM
         (selection): selection is RequireBy<ExploreSpecification, 'aggregation'> => selection.aggregation !== undefined
       );
 
-    const groupByKeys = request.groupBy?.keys ?? [];
-    const isGroupBy = groupByKeys.length > 0;
+    const groupByExpressions = request.groupBy?.keyExpressions ?? [];
+    const isGroupBy = groupByExpressions.length > 0;
 
     if (!isGroupBy && request.interval) {
       return aggregatableSpecs.map(spec => this.buildTimeseriesData(spec, result));
     }
 
     if (isGroupBy && !request.interval) {
-      return aggregatableSpecs.map(spec => this.buildGroupedSeriesData(spec, groupByKeys, result));
+      return aggregatableSpecs.map(spec => this.buildGroupedSeriesData(spec, groupByExpressions, result));
     }
 
     if (isGroupBy && request.interval) {
-      return aggregatableSpecs.map(spec => this.buildGroupedTimeseriesData(spec, groupByKeys, result)).flat();
+      return aggregatableSpecs.map(spec => this.buildGroupedTimeseriesData(spec, groupByExpressions, result)).flat();
     }
 
     return [];
@@ -149,10 +150,14 @@ export abstract class ExploreCartesianDataSourceModel extends GraphQlDataSourceM
     };
   }
 
-  public buildGroupedSeriesData(spec: AggregatableSpec, groupByKeys: string[], result: ExploreResult): SeriesData {
+  public buildGroupedSeriesData(
+    spec: AggregatableSpec,
+    groupByExpressions: AttributeExpression[],
+    result: ExploreResult
+  ): SeriesData {
     return {
       data: result
-        .getGroupedSeriesData(groupByKeys, spec.name, spec.aggregation)
+        .getGroupedSeriesData(groupByExpressions, spec.name, spec.aggregation)
         .map(({ keys, value }) => [this.buildGroupedSeriesName(keys), value]),
       spec: spec
     };
@@ -160,10 +165,10 @@ export abstract class ExploreCartesianDataSourceModel extends GraphQlDataSourceM
 
   public buildGroupedTimeseriesData(
     spec: AggregatableSpec,
-    groupByKeys: string[],
+    groupByExpressions: AttributeExpression[],
     result: ExploreResult
   ): SeriesData[] {
-    return Array.from(result.getGroupedTimeSeriesData(groupByKeys, spec.name, spec.aggregation).entries()).map(
+    return Array.from(result.getGroupedTimeSeriesData(groupByExpressions, spec.name, spec.aggregation).entries()).map(
       ([groupNames, data]) => ({
         data: data,
         groupName: this.buildGroupedSeriesName(groupNames),
diff --git a/projects/observability/src/shared/dashboard/data/graphql/explore/explore-result.test.ts b/projects/observability/src/shared/dashboard/data/graphql/explore/explore-result.test.ts
index 87afdff75..c562600e9 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/explore/explore-result.test.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/explore/explore-result.test.ts
@@ -83,7 +83,7 @@ describe('Explore result', () => {
       ]
     });
 
-    expect(result.getGroupedSeriesData(['group'], 'foo', MetricAggregationType.Sum)).toEqual([
+    expect(result.getGroupedSeriesData([{ key: 'group' }], 'foo', MetricAggregationType.Sum)).toEqual([
       { keys: ['first'], value: 10 },
       { keys: ['second'], value: 15 },
       { keys: ['third'], value: 20 }
@@ -116,7 +116,7 @@ describe('Explore result', () => {
       ]
     });
 
-    expect(result.getGroupedSeriesData(['group'], 'foo', MetricAggregationType.Sum)).toEqual([
+    expect(result.getGroupedSeriesData([{ key: 'group' }], 'foo', MetricAggregationType.Sum)).toEqual([
       { keys: ['first'], value: 10 },
       { keys: ['Others'], value: 15 }
     ]);
@@ -172,7 +172,7 @@ describe('Explore result', () => {
       ]
     });
 
-    expect(result.getGroupedTimeSeriesData(['group'], 'foo', MetricAggregationType.Sum)).toEqual(
+    expect(result.getGroupedTimeSeriesData([{ key: 'group' }], 'foo', MetricAggregationType.Sum)).toEqual(
       new Map([
         [
           ['first'],
diff --git a/projects/observability/src/shared/dashboard/data/graphql/explore/explore-result.ts b/projects/observability/src/shared/dashboard/data/graphql/explore/explore-result.ts
index 005a22a47..732df3187 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/explore/explore-result.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/explore/explore-result.ts
@@ -1,5 +1,6 @@
 import { TimeDuration } from '@hypertrace/common';
 import { groupBy } from 'lodash-es';
+import { AttributeExpression } from '../../../../graphql/model/attribute/attribute-expression';
 import { MetricTimeseriesInterval } from '../../../../graphql/model/metric/metric-timeseries';
 import { MetricAggregationType } from '../../../../graphql/model/metrics/metric-aggregation';
 import { ExploreSpecification } from '../../../../graphql/model/schema/specifications/explore-specification';
@@ -27,19 +28,25 @@ export class ExploreResult {
     return this.extractTimeseriesForSpec(this.specBuilder.exploreSpecificationForKey(metricKey, aggregation));
   }
 
-  public getGroupedSeriesData(groupKeys: string[], metricKey: string, aggregation: MetricAggregationType): GroupData[] {
+  public getGroupedSeriesData(
+    groupExpressions: AttributeExpression[],
+    metricKey: string,
+    aggregation: MetricAggregationType
+  ): GroupData[] {
     return this.extractGroupSeriesForSpec(
-      groupKeys.map(key => this.specBuilder.exploreSpecificationForKey(key)),
+      groupExpressions.map(expression => this.specBuilder.exploreSpecificationForAttributeExpression(expression)),
       this.specBuilder.exploreSpecificationForKey(metricKey, aggregation)
     );
   }
 
   public getGroupedTimeSeriesData(
-    groupKeys: string[],
+    groupExpressions: AttributeExpression[],
     metricKey: string,
     aggregation: MetricAggregationType
   ): Map<string[], MetricTimeseriesInterval[]> {
-    const groupSpecs = groupKeys.map(key => this.specBuilder.exploreSpecificationForKey(key));
+    const groupSpecs = groupExpressions.map(expression =>
+      this.specBuilder.exploreSpecificationForAttributeExpression(expression)
+    );
     const spec = this.specBuilder.exploreSpecificationForKey(metricKey, aggregation);
     const groupedResults = groupBy(this.response.results, result =>
       this.getGroupNamesFromResult(result, groupSpecs).join(',')
diff --git a/projects/observability/src/shared/dashboard/data/graphql/explorer-visualization/explorer-visualization-cartesian-data-source.model.test.ts b/projects/observability/src/shared/dashboard/data/graphql/explorer-visualization/explorer-visualization-cartesian-data-source.model.test.ts
index 836deda98..621fad703 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/explorer-visualization/explorer-visualization-cartesian-data-source.model.test.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/explorer-visualization/explorer-visualization-cartesian-data-source.model.test.ts
@@ -167,7 +167,7 @@ describe('Explorer Visualization cartesian data source model', () => {
     model.request = buildVisualizationRequest({
       interval: undefined,
       groupBy: {
-        keys: ['baz'],
+        keyExpressions: [{ key: 'baz' }],
         limit: 10
       },
       series: [
@@ -233,7 +233,7 @@ describe('Explorer Visualization cartesian data source model', () => {
     model.request = buildVisualizationRequest({
       interval: new TimeDuration(5, TimeUnit.Minute),
       groupBy: {
-        keys: ['baz'],
+        keyExpressions: [{ key: 'baz' }],
         limit: 5
       },
       series: [
diff --git a/projects/observability/src/shared/dashboard/data/graphql/graphql-data-source.module.ts b/projects/observability/src/shared/dashboard/data/graphql/graphql-data-source.module.ts
index b5150e6df..2eba63755 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/graphql-data-source.module.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/graphql-data-source.module.ts
@@ -12,7 +12,6 @@ import { SpanDataSourceModel } from './span/span-data-source.model';
 import { AttributeSpecificationModel } from './specifiers/attribute-specification.model';
 import { CompositeSpecificationModel } from './specifiers/composite-specification.model';
 import { EnrichedAttributeSpecificationModel } from './specifiers/enriched-attribute-specification.model';
-import { FieldSpecificationModel } from './specifiers/field-specification.model';
 import { MappedAttributeSpecificationModel } from './specifiers/mapped-attribute-specification.model';
 import { TraceStatusSpecificationModel } from './specifiers/trace-status-specification.model';
 import { SpansTableDataSourceModel } from './table/spans/spans-table-data-source.model';
@@ -40,7 +39,6 @@ import { TraceWaterfallDataSourceModel } from './waterfall/trace-waterfall-data-
         TracesDataSourceModel,
         CompositeSpecificationModel,
         AttributeSpecificationModel,
-        FieldSpecificationModel,
         TraceStatusSpecificationModel,
         EnrichedAttributeSpecificationModel,
         MappedAttributeSpecificationModel
diff --git a/projects/observability/src/shared/dashboard/data/graphql/metric-aggregation/metric-aggregation-data-source.model.test.ts b/projects/observability/src/shared/dashboard/data/graphql/metric-aggregation/metric-aggregation-data-source.model.test.ts
index 9ea16c3ef..46c38fb26 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/metric-aggregation/metric-aggregation-data-source.model.test.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/metric-aggregation/metric-aggregation-data-source.model.test.ts
@@ -76,7 +76,7 @@ describe('Metric aggregation data source model', () => {
         }),
         filters: [
           expect.objectContaining({
-            key: 'duration',
+            keyOrExpression: 'duration',
             operator: GraphQlOperatorType.GreaterThan,
             value: 500
           })
diff --git a/projects/observability/src/shared/dashboard/data/graphql/specifiers/field-specification.model.ts b/projects/observability/src/shared/dashboard/data/graphql/specifiers/field-specification.model.ts
deleted file mode 100644
index bdf175e99..000000000
--- a/projects/observability/src/shared/dashboard/data/graphql/specifiers/field-specification.model.ts
+++ /dev/null
@@ -1,27 +0,0 @@
-import { Dictionary } from '@hypertrace/common';
-import { Model, ModelProperty, STRING_PROPERTY } from '@hypertrace/hyperdash';
-import { Specification } from '../../../../graphql/model/schema/specifier/specification';
-import { SpecificationBuilder } from '../../../../graphql/request/builders/specification/specification-builder';
-import { SpecificationModel } from './specification.model';
-
-@Model({
-  type: 'field-specification',
-  displayName: 'Field'
-})
-export class FieldSpecificationModel extends SpecificationModel<Specification> {
-  @ModelProperty({
-    key: 'field',
-    displayName: 'Field',
-    type: STRING_PROPERTY.type,
-    required: true
-  })
-  public field!: string;
-
-  protected buildInnerSpec(): Specification {
-    return new SpecificationBuilder().fieldSpecificationForKey(this.field);
-  }
-
-  public extractFromServerData(resultContainer: Dictionary<unknown>): unknown {
-    return this.innerSpec.extractFromServerData(resultContainer);
-  }
-}
diff --git a/projects/observability/src/shared/dashboard/data/graphql/table/explore/explore-table-data-source.model.test.ts b/projects/observability/src/shared/dashboard/data/graphql/table/explore/explore-table-data-source.model.test.ts
index 689c07f08..b75ae910a 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/table/explore/explore-table-data-source.model.test.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/table/explore/explore-table-data-source.model.test.ts
@@ -187,7 +187,7 @@ describe('Explore table data source model', () => {
         limit: 100,
         offset: 0,
         groupBy: expect.objectContaining({
-          keys: ['name'],
+          keyExpressions: [{ key: 'name' }],
           includeRest: false
         }),
         orderBy: [
diff --git a/projects/observability/src/shared/dashboard/data/graphql/table/explore/explore-table-data-source.model.ts b/projects/observability/src/shared/dashboard/data/graphql/table/explore/explore-table-data-source.model.ts
index 808fd0fe1..240548e67 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/table/explore/explore-table-data-source.model.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/table/explore/explore-table-data-source.model.ts
@@ -87,7 +87,7 @@ export class ExploreTableDataSourceModel extends TableDataSourceModel {
       filters: [...filters, ...this.toGraphQlFilters(request.filters)],
       timeRange: this.getTimeRangeOrThrow(),
       groupBy: {
-        keys: this.groupBy,
+        keyExpressions: this.groupBy.map(key => ({ key: key })),
         includeRest: this.groupByIncludeRest,
         limit: this.groupLimit
       }
diff --git a/projects/observability/src/shared/dashboard/data/graphql/trace/donut/trace-donut-data-source.model.test.ts b/projects/observability/src/shared/dashboard/data/graphql/trace/donut/trace-donut-data-source.model.test.ts
index c74c1b8e4..cc6c05381 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/trace/donut/trace-donut-data-source.model.test.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/trace/donut/trace-donut-data-source.model.test.ts
@@ -63,7 +63,7 @@ describe('Donut data source model', () => {
           timeRange: GraphQlTimeRange.fromTimeRange(mockTimeRange),
           filters: [],
           groupBy: {
-            keys: ['bar'],
+            keyExpressions: [{ key: 'bar' }],
             limit: 3
           },
           limit: 3,
diff --git a/projects/observability/src/shared/dashboard/data/graphql/trace/donut/trace-donut-data-source.model.ts b/projects/observability/src/shared/dashboard/data/graphql/trace/donut/trace-donut-data-source.model.ts
index c272b9c68..0bcfc1005 100644
--- a/projects/observability/src/shared/dashboard/data/graphql/trace/donut/trace-donut-data-source.model.ts
+++ b/projects/observability/src/shared/dashboard/data/graphql/trace/donut/trace-donut-data-source.model.ts
@@ -65,7 +65,7 @@ export class TraceDonutDataSourceModel extends GraphQlDataSourceModel<DonutSerie
       timeRange: this.getTimeRangeOrThrow(),
       filters: filters,
       groupBy: {
-        keys: [this.groupBy.name],
+        keyExpressions: [{ key: this.groupBy.name }],
         limit: this.maxResults
       }
     })).pipe(map(exploreResponse => this.buildDonutResults(exploreResponse, this.metric)));
@@ -78,7 +78,7 @@ export class TraceDonutDataSourceModel extends GraphQlDataSourceModel<DonutSerie
     let total = 0;
 
     const series: DonutSeries[] = new ExploreResult(exploreResponse)
-      .getGroupedSeriesData([this.groupBy.name], metric.name, metric.aggregation)
+      .getGroupedSeriesData([{ key: this.groupBy.name }], metric.name, metric.aggregation)
       .map(seriesTuple => {
         total = total + seriesTuple.value;
 
diff --git a/projects/observability/src/shared/dashboard/widgets/top-n/data/top-n-data-source.model.test.ts b/projects/observability/src/shared/dashboard/widgets/top-n/data/top-n-data-source.model.test.ts
index f242c5ca6..d95da0557 100644
--- a/projects/observability/src/shared/dashboard/widgets/top-n/data/top-n-data-source.model.test.ts
+++ b/projects/observability/src/shared/dashboard/widgets/top-n/data/top-n-data-source.model.test.ts
@@ -61,7 +61,7 @@ describe('Top N Data Source Model', () => {
         ]),
         filters: [],
         groupBy: expect.objectContaining({
-          keys: ['nameKey', 'idKey']
+          keyExpressions: [{ key: 'nameKey' }, { key: 'idKey' }]
         })
       })
     );
diff --git a/projects/observability/src/shared/dashboard/widgets/top-n/data/top-n-data-source.model.ts b/projects/observability/src/shared/dashboard/widgets/top-n/data/top-n-data-source.model.ts
index 27d408307..45bfbccd2 100644
--- a/projects/observability/src/shared/dashboard/widgets/top-n/data/top-n-data-source.model.ts
+++ b/projects/observability/src/shared/dashboard/widgets/top-n/data/top-n-data-source.model.ts
@@ -65,7 +65,7 @@ export class TopNDataSourceModel extends GraphQlDataSourceModel<TopNWidgetDataFe
       selections: [labelAttributeSpec, idAttributeSpec, metricSpec.metric],
       filters: (filters ?? []).concat(metricSpec.filters ?? []),
       groupBy: {
-        keys: [labelAttributeSpec.name, idAttributeSpec.name],
+        keyExpressions: [{ key: labelAttributeSpec.name }, { key: idAttributeSpec.name }],
         limit: this.resultLimit
       },
       orderBy: [
diff --git a/projects/observability/src/shared/graphql/model/attribute/attribute-expression.ts b/projects/observability/src/shared/graphql/model/attribute/attribute-expression.ts
new file mode 100644
index 000000000..221e7c1f8
--- /dev/null
+++ b/projects/observability/src/shared/graphql/model/attribute/attribute-expression.ts
@@ -0,0 +1,4 @@
+export interface AttributeExpression {
+  key: string;
+  subpath?: string;
+}
diff --git a/projects/observability/src/shared/graphql/model/schema/filter/field/graphql-field-filter.ts b/projects/observability/src/shared/graphql/model/schema/filter/field/graphql-field-filter.ts
index bfc6452a4..8f2a50d9e 100644
--- a/projects/observability/src/shared/graphql/model/schema/filter/field/graphql-field-filter.ts
+++ b/projects/observability/src/shared/graphql/model/schema/filter/field/graphql-field-filter.ts
@@ -1,9 +1,11 @@
-import { GraphQlArgumentValue, GraphQlEnumArgument } from '@hypertrace/graphql-client';
+import { GraphQlArgumentObject, GraphQlArgumentValue, GraphQlEnumArgument } from '@hypertrace/graphql-client';
+import { isEmpty } from 'lodash-es';
+import { AttributeExpression } from '../../../attribute/attribute-expression';
 import { GraphQlFilter, GraphQlFilterType, GraphQlOperatorType } from '../graphql-filter';
 
 export class GraphQlFieldFilter implements GraphQlFilter {
   public constructor(
-    public readonly key: string,
+    public readonly keyOrExpression: string | AttributeExpression,
     public readonly operator: GraphQlOperatorType,
     public readonly value: GraphQlArgumentValue
   ) {}
@@ -11,18 +13,33 @@ export class GraphQlFieldFilter implements GraphQlFilter {
   public asArgumentObjects(): FieldFilter[] {
     return [
       {
-        key: this.key,
+        keyExpression: this.normalizeExpression(this.keyOrExpression),
         operator: new GraphQlEnumArgument(this.operator),
         value: this.value,
         type: new GraphQlEnumArgument(GraphQlFilterType.Attribute)
       }
     ];
   }
+
+  private normalizeExpression(
+    keyOrExpression: string | AttributeExpression
+  ): AttributeExpression & GraphQlArgumentObject {
+    if (typeof keyOrExpression === 'string') {
+      return {
+        key: keyOrExpression
+      };
+    }
+
+    return {
+      key: keyOrExpression.key,
+      ...(!isEmpty(keyOrExpression.subpath) ? { subpath: keyOrExpression.subpath } : {})
+    };
+  }
 }
 
 // tslint:disable-next-line: interface-over-type-literal https://github.com/Microsoft/TypeScript/issues/15300
 type FieldFilter = {
-  key: string;
+  keyExpression: AttributeExpression & GraphQlArgumentObject;
   value: GraphQlArgumentValue;
   operator: GraphQlEnumArgument<GraphQlOperatorType>;
   type: GraphQlEnumArgument<GraphQlFilterType>;
diff --git a/projects/observability/src/shared/graphql/model/schema/filter/graphql-filter.ts b/projects/observability/src/shared/graphql/model/schema/filter/graphql-filter.ts
index 7688a5939..c19cff0c7 100644
--- a/projects/observability/src/shared/graphql/model/schema/filter/graphql-filter.ts
+++ b/projects/observability/src/shared/graphql/model/schema/filter/graphql-filter.ts
@@ -2,7 +2,6 @@ import { GraphQlArgumentObject } from '@hypertrace/graphql-client';
 
 export interface GraphQlFilter {
   asArgumentObjects(): GraphQlArgumentObject[];
-  key: string;
 }
 
 export interface GraphQlFilterable {
diff --git a/projects/observability/src/shared/graphql/model/schema/groupby/graphql-group-by.ts b/projects/observability/src/shared/graphql/model/schema/groupby/graphql-group-by.ts
index a209a7368..342bc60ed 100644
--- a/projects/observability/src/shared/graphql/model/schema/groupby/graphql-group-by.ts
+++ b/projects/observability/src/shared/graphql/model/schema/groupby/graphql-group-by.ts
@@ -1,5 +1,7 @@
+import { AttributeExpression } from '../../attribute/attribute-expression';
+
 export interface GraphQlGroupBy {
-  keys: string[];
+  keyExpressions: AttributeExpression[];
   includeRest?: boolean;
   limit: number;
 }
diff --git a/projects/observability/src/shared/graphql/model/schema/sort/graphql-sort-argument.ts b/projects/observability/src/shared/graphql/model/schema/sort/graphql-sort-argument.ts
index a944605c8..ad8c8bef6 100644
--- a/projects/observability/src/shared/graphql/model/schema/sort/graphql-sort-argument.ts
+++ b/projects/observability/src/shared/graphql/model/schema/sort/graphql-sort-argument.ts
@@ -1,7 +1,8 @@
 import { GraphQlEnumArgument } from '@hypertrace/graphql-client';
+import { AttributeExpression } from '../../attribute/attribute-expression';
 import { GraphQlSortDirection } from './graphql-sort-direction';
 
 export interface GraphQlSortArgument {
   direction: GraphQlEnumArgument<GraphQlSortDirection>;
-  key: string;
+  expression: AttributeExpression;
 }
diff --git a/projects/observability/src/shared/graphql/request/builders/argument/graphql-argument-builder.test.ts b/projects/observability/src/shared/graphql/request/builders/argument/graphql-argument-builder.test.ts
index c3773912d..a48b0faed 100644
--- a/projects/observability/src/shared/graphql/request/builders/argument/graphql-argument-builder.test.ts
+++ b/projects/observability/src/shared/graphql/request/builders/argument/graphql-argument-builder.test.ts
@@ -15,7 +15,9 @@ describe('Graphql Argument Builder', () => {
   });
 
   test('construct arguments for attribute key correctly', () => {
-    expect(argBuilder.forAttributeKey('test-key')).toEqual(expect.objectContaining({ name: 'key', value: 'test-key' }));
+    expect(argBuilder.forAttributeKey('test-key')).toEqual(
+      expect.objectContaining({ name: 'expression', value: { key: 'test-key' } })
+    );
   });
 
   test('construct arguments for limit correctly', () => {
@@ -26,7 +28,11 @@ describe('Graphql Argument Builder', () => {
     expect(argBuilder.forOrderBy(undefined)).toEqual(expect.arrayContaining([]));
     expect(
       argBuilder.forOrderBy({ direction: 'ASC', key: specBuilder.attributeSpecificationForKey('test-key') })
-    ).toEqual(expect.arrayContaining([{ name: 'orderBy', value: [{ direction: { value: 'ASC' }, key: 'test-key' }] }]));
+    ).toEqual(
+      expect.arrayContaining([
+        { name: 'orderBy', value: [{ direction: { value: 'ASC' }, keyExpression: { key: 'test-key' } }] }
+      ])
+    );
   });
 
   test('construct arguments for orderBys correctly', () => {
@@ -41,8 +47,8 @@ describe('Graphql Argument Builder', () => {
         {
           name: 'orderBy',
           value: [
-            { direction: { value: 'ASC' }, key: 'test-key' },
-            { direction: { value: 'ASC' }, key: 'test-key2' }
+            { direction: { value: 'ASC' }, keyExpression: { key: 'test-key' } },
+            { direction: { value: 'ASC' }, keyExpression: { key: 'test-key2' } }
           ]
         }
       ])
@@ -82,7 +88,12 @@ describe('Graphql Argument Builder', () => {
         {
           name: 'filterBy',
           value: [
-            { key: 'filter-key', operator: { value: 'EQUALS' }, type: { value: 'ATTRIBUTE' }, value: 'filter-value' }
+            {
+              keyExpression: { key: 'filter-key' },
+              operator: { value: 'EQUALS' },
+              type: { value: 'ATTRIBUTE' },
+              value: 'filter-value'
+            }
           ]
         }
       ])
diff --git a/projects/observability/src/shared/graphql/request/builders/argument/graphql-argument-builder.ts b/projects/observability/src/shared/graphql/request/builders/argument/graphql-argument-builder.ts
index a55a06143..abc21b9d4 100644
--- a/projects/observability/src/shared/graphql/request/builders/argument/graphql-argument-builder.ts
+++ b/projects/observability/src/shared/graphql/request/builders/argument/graphql-argument-builder.ts
@@ -1,4 +1,6 @@
-import { GraphQlArgument, GraphQlEnumArgument } from '@hypertrace/graphql-client';
+import { GraphQlArgument, GraphQlArgumentObject, GraphQlEnumArgument } from '@hypertrace/graphql-client';
+import { isEmpty, omit } from 'lodash-es';
+import { AttributeExpression } from '../../../model/attribute/attribute-expression';
 import { GraphQlFilter } from '../../../model/schema/filter/graphql-filter';
 import { GraphQlSortBySpecification } from '../../../model/schema/sort/graphql-sort-by-specification';
 import { GraphQlTimeRange } from '../../../model/schema/timerange/graphql-time-range';
@@ -10,9 +12,13 @@ export class GraphQlArgumentBuilder {
   }
 
   public forAttributeKey(key: string): GraphQlArgument {
+    return this.forAttributeExpression({ key: key });
+  }
+
+  public forAttributeExpression(attributeExpression: AttributeExpression): GraphQlArgument {
     return {
-      name: 'key',
-      value: key
+      name: 'expression',
+      value: this.buildAttributeExpression(attributeExpression)
     };
   }
 
@@ -32,10 +38,7 @@ export class GraphQlArgumentBuilder {
     return [
       {
         name: 'orderBy',
-        value: orderBys.map(orderBy => ({
-          ...orderBy.key.asGraphQlOrderByFragment(),
-          direction: new GraphQlEnumArgument(orderBy.direction)
-        }))
+        value: orderBys.map(orderBy => this.buildOrderByArgumentValue(orderBy))
       }
     ];
   }
@@ -77,4 +80,24 @@ export class GraphQlArgumentBuilder {
   public forScope(scope: string): GraphQlArgument {
     return { name: 'scope', value: scope };
   }
+
+  protected buildAttributeExpression(
+    attributeExpression: AttributeExpression
+  ): AttributeExpression & GraphQlArgumentObject {
+    return {
+      key: attributeExpression.key,
+      ...(!isEmpty(attributeExpression.subpath) ? { subpath: attributeExpression.subpath } : {})
+    };
+  }
+
+  protected buildOrderByArgumentValue(orderBy: GraphQlSortBySpecification): GraphQlArgumentObject {
+    const orderByFragment = orderBy.key.asGraphQlOrderByFragment();
+    const unknownFields = omit(orderByFragment, 'direction', 'expression');
+
+    return {
+      ...unknownFields,
+      direction: new GraphQlEnumArgument(orderBy.direction),
+      keyExpression: this.buildAttributeExpression(orderByFragment.expression)
+    };
+  }
 }
diff --git a/projects/observability/src/shared/graphql/request/builders/argument/graphql-observability-argument-builder.ts b/projects/observability/src/shared/graphql/request/builders/argument/graphql-observability-argument-builder.ts
index 4aebf06d1..1f0801c3b 100644
--- a/projects/observability/src/shared/graphql/request/builders/argument/graphql-observability-argument-builder.ts
+++ b/projects/observability/src/shared/graphql/request/builders/argument/graphql-observability-argument-builder.ts
@@ -1,11 +1,11 @@
 import { TimeDuration } from '@hypertrace/common';
 import { GraphQlArgument, GraphQlEnumArgument } from '@hypertrace/graphql-client';
+import { isNil } from 'lodash-es';
 import { MetricAggregationType } from '../../../model/metrics/metric-aggregation';
 import { EntityType } from '../../../model/schema/entity';
 import { GraphQlGroupBy } from '../../../model/schema/groupby/graphql-group-by';
 import { GraphQlIntervalUnit } from '../../../model/schema/interval/graphql-interval-unit';
 import { convertToGraphQlMetricAggregationType } from '../../../model/schema/metrics/graphql-metric-aggregation-type';
-import { GraphQlSortBySpecification } from '../../../model/schema/sort/graphql-sort-by-specification';
 import { TraceType } from '../../../model/schema/trace';
 import { convertToGraphQlIntervalUnit } from '../specification/metric/metric-interval-unit-converter';
 import { GraphQlArgumentBuilder } from './graphql-argument-builder';
@@ -101,26 +101,6 @@ export class GraphQlObservabilityArgumentBuilder extends GraphQlArgumentBuilder
       : [{ name: 'aggregation', value: new GraphQlEnumArgument(convertToGraphQlMetricAggregationType(aggregation)) }];
   }
 
-  public forOrderBy(orderBy?: GraphQlSortBySpecification): GraphQlArgument[] {
-    return this.forOrderBys(orderBy && [orderBy]);
-  }
-
-  public forOrderBys(orderBys: GraphQlSortBySpecification[] = []): GraphQlArgument[] {
-    if (orderBys.length === 0) {
-      return [];
-    }
-
-    return [
-      {
-        name: 'orderBy',
-        value: orderBys.map(orderBy => ({
-          ...orderBy.key.asGraphQlOrderByFragment(),
-          direction: new GraphQlEnumArgument(orderBy.direction)
-        }))
-      }
-    ];
-  }
-
   public forGroupBy(groupBy?: GraphQlGroupBy): GraphQlArgument[] {
     if (!groupBy) {
       return [];
@@ -129,18 +109,11 @@ export class GraphQlObservabilityArgumentBuilder extends GraphQlArgumentBuilder
     return [
       {
         name: 'groupBy',
-        value:
-          // Remove includeRest key if undefined
-          groupBy.includeRest === undefined
-            ? {
-                keys: groupBy.keys,
-                groupLimit: groupBy.limit
-              }
-            : {
-                keys: groupBy.keys,
-                groupLimit: groupBy.limit,
-                includeRest: groupBy.includeRest
-              }
+        value: {
+          expressions: groupBy.keyExpressions.map(expression => this.buildAttributeExpression(expression)),
+          groupLimit: groupBy.limit,
+          ...(isNil(groupBy.includeRest) ? {} : { includeRest: groupBy.includeRest })
+        }
       }
     ];
   }
diff --git a/projects/observability/src/shared/graphql/request/builders/selections/observability-specification-builder.ts b/projects/observability/src/shared/graphql/request/builders/selections/observability-specification-builder.ts
index 47183bf2d..86b43b1f0 100644
--- a/projects/observability/src/shared/graphql/request/builders/selections/observability-specification-builder.ts
+++ b/projects/observability/src/shared/graphql/request/builders/selections/observability-specification-builder.ts
@@ -297,7 +297,7 @@ export class ObservabilitySpecificationBuilder extends SpecificationBuilder {
       name: metric,
       aggregation: aggregation,
       asGraphQlOrderByFragment: () => ({
-        key: metric,
+        expression: { key: metric },
         aggregation: this.aggregationAsEnum(aggregation)
       })
     };
diff --git a/projects/observability/src/shared/graphql/request/builders/specification/attribute/enriched-attribute-specification-builder.test.ts b/projects/observability/src/shared/graphql/request/builders/specification/attribute/enriched-attribute-specification-builder.test.ts
index 161465c74..ad85f6c30 100644
--- a/projects/observability/src/shared/graphql/request/builders/specification/attribute/enriched-attribute-specification-builder.test.ts
+++ b/projects/observability/src/shared/graphql/request/builders/specification/attribute/enriched-attribute-specification-builder.test.ts
@@ -11,8 +11,8 @@ describe('EnrichedAttributeSpecificationBuilder', () => {
       alias: 'duration',
       arguments: [
         {
-          name: 'key',
-          value: 'duration'
+          name: 'expression',
+          value: { key: 'duration' }
         }
       ]
     });
diff --git a/projects/observability/src/shared/graphql/request/builders/specification/attribute/enriched-attribute-specification-builder.ts b/projects/observability/src/shared/graphql/request/builders/specification/attribute/enriched-attribute-specification-builder.ts
index 3dcaefcf0..aafcb5834 100644
--- a/projects/observability/src/shared/graphql/request/builders/specification/attribute/enriched-attribute-specification-builder.ts
+++ b/projects/observability/src/shared/graphql/request/builders/specification/attribute/enriched-attribute-specification-builder.ts
@@ -13,7 +13,7 @@ export class EnrichedAttributeSpecificationBuilder {
       asGraphQlSelections: () => this.buildGraphQlSelections(attributeKey),
       extractFromServerData: serverData => this.extractFromServerData(attributeKey, units, serverData),
       asGraphQlOrderByFragment: () => ({
-        key: attributeKey
+        expression: { key: attributeKey }
       })
     };
   }
diff --git a/projects/observability/src/shared/graphql/request/builders/specification/entity/entity-specification-builder.test.ts b/projects/observability/src/shared/graphql/request/builders/specification/entity/entity-specification-builder.test.ts
index b4faf9711..16bbc89b8 100644
--- a/projects/observability/src/shared/graphql/request/builders/specification/entity/entity-specification-builder.test.ts
+++ b/projects/observability/src/shared/graphql/request/builders/specification/entity/entity-specification-builder.test.ts
@@ -18,8 +18,8 @@ describe('Entity Specification Builder', () => {
         alias: 'id',
         arguments: [
           {
-            name: 'key',
-            value: 'id'
+            name: 'expression',
+            value: { key: 'id' }
           }
         ]
       },
@@ -28,8 +28,8 @@ describe('Entity Specification Builder', () => {
         alias: 'name',
         arguments: [
           {
-            name: 'key',
-            value: 'name'
+            name: 'expression',
+            value: { key: 'name' }
           }
         ]
       },
@@ -38,8 +38,8 @@ describe('Entity Specification Builder', () => {
         alias: 'attribute1',
         arguments: [
           {
-            name: 'key',
-            value: 'attribute1'
+            name: 'expression',
+            value: { key: 'attribute1' }
           }
         ]
       },
@@ -48,8 +48,8 @@ describe('Entity Specification Builder', () => {
         alias: 'attribute2',
         arguments: [
           {
-            name: 'key',
-            value: 'attribute2'
+            name: 'expression',
+            value: { key: 'attribute2' }
           }
         ]
       }
@@ -89,8 +89,8 @@ describe('Entity Specification Builder', () => {
         alias: 'id',
         arguments: [
           {
-            name: 'key',
-            value: 'id'
+            name: 'expression',
+            value: { key: 'id' }
           }
         ]
       },
@@ -99,8 +99,8 @@ describe('Entity Specification Builder', () => {
         alias: 'name',
         arguments: [
           {
-            name: 'key',
-            value: 'name'
+            name: 'expression',
+            value: { key: 'name' }
           }
         ]
       },
@@ -109,8 +109,8 @@ describe('Entity Specification Builder', () => {
         alias: 'attribute1',
         arguments: [
           {
-            name: 'key',
-            value: 'attribute1'
+            name: 'expression',
+            value: { key: 'attribute1' }
           }
         ]
       },
@@ -119,8 +119,8 @@ describe('Entity Specification Builder', () => {
         alias: 'attribute2',
         arguments: [
           {
-            name: 'key',
-            value: 'attribute2'
+            name: 'expression',
+            value: { key: 'attribute2' }
           }
         ]
       },
@@ -129,8 +129,8 @@ describe('Entity Specification Builder', () => {
         alias: 'status',
         arguments: [
           {
-            name: 'key',
-            value: 'status'
+            name: 'expression',
+            value: { key: 'status' }
           }
         ]
       },
@@ -139,8 +139,8 @@ describe('Entity Specification Builder', () => {
         alias: 'statusCode',
         arguments: [
           {
-            name: 'key',
-            value: 'statusCode'
+            name: 'expression',
+            value: { key: 'statusCode' }
           }
         ]
       },
@@ -149,8 +149,8 @@ describe('Entity Specification Builder', () => {
         alias: 'statusMessage',
         arguments: [
           {
-            name: 'key',
-            value: 'statusMessage'
+            name: 'expression',
+            value: { key: 'statusMessage' }
           }
         ]
       }
@@ -189,8 +189,8 @@ describe('Entity Specification Builder', () => {
         alias: 'id',
         arguments: [
           {
-            name: 'key',
-            value: 'id'
+            name: 'expression',
+            value: { key: 'id' }
           }
         ]
       },
@@ -199,8 +199,8 @@ describe('Entity Specification Builder', () => {
         alias: 'name',
         arguments: [
           {
-            name: 'key',
-            value: 'name'
+            name: 'expression',
+            value: { key: 'name' }
           }
         ]
       },
@@ -231,8 +231,8 @@ describe('Entity Specification Builder', () => {
         alias: 'id',
         arguments: [
           {
-            name: 'key',
-            value: 'id'
+            name: 'expression',
+            value: { key: 'id' }
           }
         ]
       },
@@ -241,8 +241,8 @@ describe('Entity Specification Builder', () => {
         alias: 'name',
         arguments: [
           {
-            name: 'key',
-            value: 'name'
+            name: 'expression',
+            value: { key: 'name' }
           }
         ]
       },
diff --git a/projects/observability/src/shared/graphql/request/builders/specification/entity/entity-specification-builder.ts b/projects/observability/src/shared/graphql/request/builders/specification/entity/entity-specification-builder.ts
index 0f46ffad4..0c38ab0bf 100644
--- a/projects/observability/src/shared/graphql/request/builders/specification/entity/entity-specification-builder.ts
+++ b/projects/observability/src/shared/graphql/request/builders/specification/entity/entity-specification-builder.ts
@@ -44,7 +44,7 @@ export class EntitySpecificationBuilder {
           additionalSpecifications
         ),
       asGraphQlOrderByFragment: () => ({
-        key: nameKey
+        expression: { key: nameKey }
       })
     };
   }
diff --git a/projects/observability/src/shared/graphql/request/builders/specification/explore/explore-specification-builder.ts b/projects/observability/src/shared/graphql/request/builders/specification/explore/explore-specification-builder.ts
index 627e3a41d..e1742a94d 100644
--- a/projects/observability/src/shared/graphql/request/builders/specification/explore/explore-specification-builder.ts
+++ b/projects/observability/src/shared/graphql/request/builders/specification/explore/explore-specification-builder.ts
@@ -1,5 +1,7 @@
 import { DateCoercer, Dictionary } from '@hypertrace/common';
 import { GraphQlEnumArgument } from '@hypertrace/graphql-client';
+import { isEmpty } from 'lodash-es';
+import { AttributeExpression } from '../../../../model/attribute/attribute-expression';
 import { AttributeMetadataType } from '../../../../model/metadata/attribute-metadata';
 import { MetricAggregationType } from '../../../../model/metrics/metric-aggregation';
 import { INTERVAL_START_QUERY_KEY } from '../../../../model/schema/explore';
@@ -25,23 +27,31 @@ export class ExploreSpecificationBuilder {
         type: AttributeMetadataType.Timestamp
       }),
       asGraphQlOrderByFragment: () => ({
-        key: 'intervalStart'
+        expression: { key: 'intervalStart' }
       })
     };
   }
 
   public exploreSpecificationForKey(key: string, aggregation?: MetricAggregationType): ExploreSpecification {
-    const queryAlias = aggregation === undefined ? key : `${aggregation}_${key}`;
+    return this.exploreSpecificationForAttributeExpression({ key: key }, aggregation);
+  }
+
+  public exploreSpecificationForAttributeExpression(
+    expression: AttributeExpression,
+    aggregation?: MetricAggregationType
+  ): ExploreSpecification {
+    const expressionString = this.attributeExpressionAsString(expression);
+    const queryAlias = aggregation === undefined ? expressionString : `${aggregation}_${expressionString}`;
 
     return {
-      resultAlias: () => this.buildResultAlias(key, aggregation),
-      name: key,
+      resultAlias: () => this.buildResultAlias(expression, aggregation),
+      name: expressionString,
       aggregation: aggregation,
       asGraphQlSelections: () => ({
         path: 'selection',
         alias: queryAlias,
         arguments: [
-          this.argBuilder.forAttributeKey(key),
+          this.argBuilder.forAttributeExpression(expression),
           ...this.argBuilder.forAggregation(aggregation),
           ...this.argBuilder.forAggregationArgs(aggregation)
         ],
@@ -50,7 +60,7 @@ export class ExploreSpecificationBuilder {
       extractFromServerData: serverData => serverData[queryAlias],
       asGraphQlOrderByFragment: () => {
         const fragment: GraphQlSortWithoutDirection & Dictionary<unknown> = {
-          key: key
+          expression: expression
         };
 
         if (aggregation !== undefined) {
@@ -62,8 +72,14 @@ export class ExploreSpecificationBuilder {
     };
   }
 
-  protected buildResultAlias(key: string, aggregation?: MetricAggregationType): string {
-    return aggregation === undefined ? key : `${aggregation}(${key})`;
+  protected attributeExpressionAsString(expression: AttributeExpression): string {
+    return isEmpty(expression.subpath) ? expression.key : `${expression.key}.${expression.subpath}`;
+  }
+
+  protected buildResultAlias(expression: AttributeExpression, aggregation?: MetricAggregationType): string {
+    const expressionString = this.attributeExpressionAsString(expression);
+
+    return aggregation === undefined ? expressionString : `${aggregation}(${expressionString})`;
   }
 
   protected aggregationAsEnum(aggregation: MetricAggregationType): GraphQlEnumArgument<GraphQlMetricAggregationType> {
diff --git a/projects/observability/src/shared/graphql/request/builders/specification/specification-builder.test.ts b/projects/observability/src/shared/graphql/request/builders/specification/specification-builder.test.ts
index eb0859c0f..a60d4faf9 100644
--- a/projects/observability/src/shared/graphql/request/builders/specification/specification-builder.test.ts
+++ b/projects/observability/src/shared/graphql/request/builders/specification/specification-builder.test.ts
@@ -9,18 +9,4 @@ describe('Specification Builder', () => {
       })
     ).toBeUndefined();
   });
-
-  test('field specs should build correct selection and response', () => {
-    const fieldSpec = specBuilder.fieldSpecificationForKey('test');
-
-    expect(fieldSpec.resultAlias()).toEqual('test');
-    expect(fieldSpec.name).toEqual('test');
-
-    expect(fieldSpec.asGraphQlSelections()).toEqual({ path: 'test' });
-    expect(fieldSpec.extractFromServerData({ test: 'null' })).toBeUndefined();
-
-    expect(fieldSpec.extractFromServerData({ test: 'test value' })).toEqual('test value');
-
-    expect(fieldSpec.asGraphQlOrderByFragment()).toEqual({ key: 'test' });
-  });
 });
diff --git a/projects/observability/src/shared/graphql/request/builders/specification/specification-builder.ts b/projects/observability/src/shared/graphql/request/builders/specification/specification-builder.ts
index 924080935..e1519addf 100644
--- a/projects/observability/src/shared/graphql/request/builders/specification/specification-builder.ts
+++ b/projects/observability/src/shared/graphql/request/builders/specification/specification-builder.ts
@@ -20,7 +20,7 @@ export class SpecificationBuilder {
       extractFromServerData: serverData =>
         specifications.map(specification => specification.extractFromServerData(serverData)),
       asGraphQlOrderByFragment: () => ({
-        key: orderByKey
+        expression: { key: orderByKey }
       })
     };
   }
@@ -44,25 +44,7 @@ export class SpecificationBuilder {
         return serverValue === 'null' ? undefined : serverValue;
       },
       asGraphQlOrderByFragment: () => ({
-        key: attributeKey
-      })
-    };
-  }
-
-  public fieldSpecificationForKey(field: string): Specification {
-    return {
-      resultAlias: () => field,
-      name: field,
-      asGraphQlSelections: () => ({
-        path: field
-      }),
-      extractFromServerData: serverData => {
-        const serverValue = serverData[field];
-
-        return serverValue === 'null' ? undefined : serverValue;
-      },
-      asGraphQlOrderByFragment: () => ({
-        key: field
+        expression: { key: attributeKey }
       })
     };
   }
diff --git a/projects/observability/src/shared/graphql/request/builders/specification/trace/trace-status/trace-status-specification-builder.test.ts b/projects/observability/src/shared/graphql/request/builders/specification/trace/trace-status/trace-status-specification-builder.test.ts
index b9eb6f6d5..d52f31832 100644
--- a/projects/observability/src/shared/graphql/request/builders/specification/trace/trace-status/trace-status-specification-builder.test.ts
+++ b/projects/observability/src/shared/graphql/request/builders/specification/trace/trace-status/trace-status-specification-builder.test.ts
@@ -13,8 +13,8 @@ describe('TraceStatusSpecificationBuilder', () => {
         alias: 'status',
         arguments: [
           {
-            name: 'key',
-            value: 'status'
+            name: 'expression',
+            value: { key: 'status' }
           }
         ]
       },
@@ -23,8 +23,8 @@ describe('TraceStatusSpecificationBuilder', () => {
         alias: 'statusCode',
         arguments: [
           {
-            name: 'key',
-            value: 'statusCode'
+            name: 'expression',
+            value: { key: 'statusCode' }
           }
         ]
       },
@@ -33,8 +33,8 @@ describe('TraceStatusSpecificationBuilder', () => {
         alias: 'statusMessage',
         arguments: [
           {
-            name: 'key',
-            value: 'statusMessage'
+            name: 'expression',
+            value: { key: 'statusMessage' }
           }
         ]
       }
diff --git a/projects/observability/src/shared/graphql/request/builders/specification/trace/trace-status/trace-status-specification-builder.ts b/projects/observability/src/shared/graphql/request/builders/specification/trace/trace-status/trace-status-specification-builder.ts
index 025d557f0..e57e83f40 100644
--- a/projects/observability/src/shared/graphql/request/builders/specification/trace/trace-status/trace-status-specification-builder.ts
+++ b/projects/observability/src/shared/graphql/request/builders/specification/trace/trace-status/trace-status-specification-builder.ts
@@ -17,7 +17,7 @@ export class TraceStatusSpecificationBuilder {
       name: TraceStatusSpecificationBuilder.STATUS_CODE_FIELD,
       asGraphQlSelections: () => this.buildGraphQlSelections(),
       extractFromServerData: serverData => this.extractFromServerData(serverData),
-      asGraphQlOrderByFragment: () => ({ key: TraceStatusSpecificationBuilder.STATUS_CODE_FIELD })
+      asGraphQlOrderByFragment: () => ({ expression: { key: TraceStatusSpecificationBuilder.STATUS_CODE_FIELD } })
     };
   }
 
diff --git a/projects/observability/src/shared/graphql/request/handlers/entities/query/entities-graphql-query-handler.service.test.ts b/projects/observability/src/shared/graphql/request/handlers/entities/query/entities-graphql-query-handler.service.test.ts
index 1ad28b8aa..a3a5d1c95 100644
--- a/projects/observability/src/shared/graphql/request/handlers/entities/query/entities-graphql-query-handler.service.test.ts
+++ b/projects/observability/src/shared/graphql/request/handlers/entities/query/entities-graphql-query-handler.service.test.ts
@@ -94,7 +94,7 @@ describe('Entities graphql query handler', () => {
           {
             path: 'attribute',
             alias: 'name',
-            arguments: [{ name: 'key', value: 'name' }]
+            arguments: [{ name: 'expression', value: { key: 'name' } }]
           }
         ]
       },
@@ -217,7 +217,7 @@ describe('Entities graphql query handler', () => {
             {
               path: 'metric',
               alias: 'some_metric',
-              arguments: [{ name: 'key', value: 'some_metric' }],
+              arguments: [{ name: 'expression', value: { key: 'some_metric' } }],
               children: [
                 {
                   alias: 'avgrate_min',
@@ -234,7 +234,7 @@ describe('Entities graphql query handler', () => {
             {
               path: 'metric',
               alias: 'some_metric',
-              arguments: [{ name: 'key', value: 'some_metric' }],
+              arguments: [{ name: 'expression', value: { key: 'some_metric' } }],
               children: [
                 {
                   alias: 'avgrate_sec',
@@ -343,7 +343,7 @@ describe('Entities graphql query handler', () => {
             {
               path: 'metric',
               alias: 'a_metric',
-              arguments: [{ name: 'key', value: 'a_metric' }],
+              arguments: [{ name: 'expression', value: { key: 'a_metric' } }],
               children: [
                 {
                   alias: 'min_series_1m',
@@ -362,7 +362,7 @@ describe('Entities graphql query handler', () => {
             {
               path: 'metric',
               alias: 'a_metric',
-              arguments: [{ name: 'key', value: 'a_metric' }],
+              arguments: [{ name: 'expression', value: { key: 'a_metric' } }],
               children: [
                 {
                   alias: 'max_series_1m',
@@ -382,7 +382,7 @@ describe('Entities graphql query handler', () => {
             {
               path: 'metric',
               alias: 'a_metric',
-              arguments: [{ name: 'key', value: 'a_metric' }],
+              arguments: [{ name: 'expression', value: { key: 'a_metric' } }],
               children: [
                 {
                   alias: 'min_series_5m',
diff --git a/projects/observability/src/shared/graphql/request/handlers/entities/query/interactions/interactions-graphql-query-handler.service.test.ts b/projects/observability/src/shared/graphql/request/handlers/entities/query/interactions/interactions-graphql-query-handler.service.test.ts
index 9daeb73ed..b6b5d8433 100644
--- a/projects/observability/src/shared/graphql/request/handlers/entities/query/interactions/interactions-graphql-query-handler.service.test.ts
+++ b/projects/observability/src/shared/graphql/request/handlers/entities/query/interactions/interactions-graphql-query-handler.service.test.ts
@@ -110,7 +110,7 @@ describe('Interactions graphql query handler', () => {
                     {
                       path: 'metric',
                       alias: 'duration',
-                      arguments: [{ name: 'key', value: 'duration' }],
+                      arguments: [{ name: 'expression', value: { key: 'duration' } }],
                       children: [
                         {
                           path: 'avg',
@@ -124,7 +124,11 @@ describe('Interactions graphql query handler', () => {
                       path: 'neighbor',
                       children: [
                         { path: 'id' },
-                        { path: 'attribute', alias: 'name', arguments: [{ name: 'key', value: 'name' }] }
+                        {
+                          path: 'attribute',
+                          alias: 'name',
+                          arguments: [{ name: 'expression', value: { key: 'name' } }]
+                        }
                       ]
                     }
                   ]
diff --git a/projects/observability/src/shared/graphql/request/handlers/entities/query/topology/entity-topology-graphql-query-handler.service.test.ts b/projects/observability/src/shared/graphql/request/handlers/entities/query/topology/entity-topology-graphql-query-handler.service.test.ts
index b61a9f3f4..19d3139b8 100644
--- a/projects/observability/src/shared/graphql/request/handlers/entities/query/topology/entity-topology-graphql-query-handler.service.test.ts
+++ b/projects/observability/src/shared/graphql/request/handlers/entities/query/topology/entity-topology-graphql-query-handler.service.test.ts
@@ -259,11 +259,11 @@ describe('Entity topology graphql query handler', () => {
           path: 'results',
           children: [
             { path: 'id' },
-            { path: 'attribute', alias: 'name', arguments: [{ name: 'key', value: 'name' }] },
+            { path: 'attribute', alias: 'name', arguments: [{ name: 'expression', value: { key: 'name' } }] },
             {
               path: 'metric',
               alias: 'duration',
-              arguments: [{ name: 'key', value: 'duration' }],
+              arguments: [{ name: 'expression', value: { key: 'duration' } }],
               children: [
                 {
                   path: 'avg',
@@ -284,7 +284,7 @@ describe('Entity topology graphql query handler', () => {
                     {
                       path: 'metric',
                       alias: 'duration',
-                      arguments: [{ name: 'key', value: 'duration' }],
+                      arguments: [{ name: 'expression', value: { key: 'duration' } }],
                       children: [
                         {
                           path: 'avg',
@@ -298,12 +298,20 @@ describe('Entity topology graphql query handler', () => {
                       path: 'neighbor',
                       children: [
                         { path: 'id' },
-                        { path: 'attribute', alias: 'name', arguments: [{ name: 'key', value: 'name' }] },
-                        { path: 'attribute', alias: 'type', arguments: [{ name: 'key', value: 'type' }] },
+                        {
+                          path: 'attribute',
+                          alias: 'name',
+                          arguments: [{ name: 'expression', value: { key: 'name' } }]
+                        },
+                        {
+                          path: 'attribute',
+                          alias: 'type',
+                          arguments: [{ name: 'expression', value: { key: 'type' } }]
+                        },
                         {
                           path: 'metric',
                           alias: 'numCalls',
-                          arguments: [{ name: 'key', value: 'numCalls' }],
+                          arguments: [{ name: 'expression', value: { key: 'numCalls' } }],
                           children: [
                             {
                               path: 'avgrate',
@@ -333,7 +341,7 @@ describe('Entity topology graphql query handler', () => {
                     {
                       path: 'metric',
                       alias: 'duration',
-                      arguments: [{ name: 'key', value: 'duration' }],
+                      arguments: [{ name: 'expression', value: { key: 'duration' } }],
                       children: [
                         {
                           path: 'avg',
@@ -347,11 +355,15 @@ describe('Entity topology graphql query handler', () => {
                       path: 'neighbor',
                       children: [
                         { path: 'id' },
-                        { path: 'attribute', alias: 'name', arguments: [{ name: 'key', value: 'name' }] },
+                        {
+                          path: 'attribute',
+                          alias: 'name',
+                          arguments: [{ name: 'expression', value: { key: 'name' } }]
+                        },
                         {
                           path: 'metric',
                           alias: 'duration',
-                          arguments: [{ name: 'key', value: 'duration' }],
+                          arguments: [{ name: 'expression', value: { key: 'duration' } }],
                           children: [
                             {
                               path: 'avg',
@@ -378,7 +390,7 @@ describe('Entity topology graphql query handler', () => {
                     {
                       path: 'metric',
                       alias: 'duration',
-                      arguments: [{ name: 'key', value: 'duration' }],
+                      arguments: [{ name: 'expression', value: { key: 'duration' } }],
                       children: [
                         {
                           path: 'avg',
@@ -392,11 +404,15 @@ describe('Entity topology graphql query handler', () => {
                       path: 'neighbor',
                       children: [
                         { path: 'id' },
-                        { path: 'attribute', alias: 'name', arguments: [{ name: 'key', value: 'name' }] },
+                        {
+                          path: 'attribute',
+                          alias: 'name',
+                          arguments: [{ name: 'expression', value: { key: 'name' } }]
+                        },
                         {
                           path: 'metric',
                           alias: 'duration',
-                          arguments: [{ name: 'key', value: 'duration' }],
+                          arguments: [{ name: 'expression', value: { key: 'duration' } }],
                           children: [
                             {
                               path: 'avg',
diff --git a/projects/observability/src/shared/graphql/request/handlers/explore/explore-graphql-query-builder.service.ts b/projects/observability/src/shared/graphql/request/handlers/explore/explore-graphql-query-builder.service.ts
index 8337583d2..eb00e23d8 100644
--- a/projects/observability/src/shared/graphql/request/handlers/explore/explore-graphql-query-builder.service.ts
+++ b/projects/observability/src/shared/graphql/request/handlers/explore/explore-graphql-query-builder.service.ts
@@ -102,6 +102,8 @@ export class ExploreGraphqlQueryBuilderService {
   }
 
   private groupByAsSpecifications(groupBy?: GraphQlGroupBy): ExploreSpecification[] {
-    return (groupBy?.keys ?? []).map(key => this.specBuilder.exploreSpecificationForKey(key));
+    return (groupBy?.keyExpressions ?? []).map(expression =>
+      this.specBuilder.exploreSpecificationForAttributeExpression(expression)
+    );
   }
 }
diff --git a/projects/observability/src/shared/graphql/request/handlers/explore/explore-graphql-query-handler.service.test.ts b/projects/observability/src/shared/graphql/request/handlers/explore/explore-graphql-query-handler.service.test.ts
index 8b51596b6..4a240fc89 100644
--- a/projects/observability/src/shared/graphql/request/handlers/explore/explore-graphql-query-handler.service.test.ts
+++ b/projects/observability/src/shared/graphql/request/handlers/explore/explore-graphql-query-handler.service.test.ts
@@ -57,7 +57,7 @@ describe('Explore graphql query handler', () => {
     groupBy: {
       limit: 2,
       includeRest: true,
-      keys: ['serviceName']
+      keyExpressions: [{ key: 'serviceName' }]
     },
     orderBy: [
       {
@@ -98,13 +98,13 @@ describe('Explore graphql query handler', () => {
           name: 'filterBy',
           value: [
             {
-              key: 'duration',
+              keyExpression: { key: 'duration' },
               operator: new GraphQlEnumArgument(GraphQlOperatorType.GreaterThan),
               value: 0,
               type: new GraphQlEnumArgument(GraphQlFilterType.Attribute)
             },
             {
-              key: 'duration',
+              keyExpression: { key: 'duration' },
               operator: new GraphQlEnumArgument(GraphQlOperatorType.LessThan),
               value: 100,
               type: new GraphQlEnumArgument(GraphQlFilterType.Attribute)
@@ -115,7 +115,7 @@ describe('Explore graphql query handler', () => {
           name: 'groupBy',
           value: {
             includeRest: true,
-            keys: ['serviceName'],
+            expressions: [{ key: 'serviceName' }],
             groupLimit: 2
           }
         },
@@ -124,7 +124,7 @@ describe('Explore graphql query handler', () => {
           value: [
             {
               direction: new GraphQlEnumArgument('ASC'),
-              key: 'duration',
+              keyExpression: { key: 'duration' },
               aggregation: new GraphQlEnumArgument(GraphQlMetricAggregationType.Average)
             }
           ]
@@ -138,14 +138,14 @@ describe('Explore graphql query handler', () => {
             {
               path: 'selection',
               alias: 'serviceName',
-              arguments: [{ name: 'key', value: 'serviceName' }],
+              arguments: [{ name: 'expression', value: { key: 'serviceName' } }],
               children: [{ path: 'value' }, { path: 'type' }]
             },
             {
               path: 'selection',
               alias: 'avg_duration',
               arguments: [
-                { name: 'key', value: 'duration' },
+                { name: 'expression', value: { key: 'duration' } },
                 { name: 'aggregation', value: new GraphQlEnumArgument(GraphQlMetricAggregationType.Average) }
               ],
               children: [{ path: 'value' }, { path: 'type' }]
@@ -154,7 +154,7 @@ describe('Explore graphql query handler', () => {
               path: 'selection',
               alias: 'avgrate_min_duration',
               arguments: [
-                { name: 'key', value: 'duration' },
+                { name: 'expression', value: { key: 'duration' } },
                 { name: 'aggregation', value: new GraphQlEnumArgument(GraphQlMetricAggregationType.Avgrate) },
                 { name: 'units', value: new GraphQlEnumArgument(GraphQlIntervalUnit.Minutes) },
                 { name: 'size', value: 1 }
@@ -193,13 +193,13 @@ describe('Explore graphql query handler', () => {
           name: 'filterBy',
           value: [
             {
-              key: 'duration',
+              keyExpression: { key: 'duration' },
               operator: new GraphQlEnumArgument(GraphQlOperatorType.GreaterThan),
               value: 0,
               type: new GraphQlEnumArgument(GraphQlFilterType.Attribute)
             },
             {
-              key: 'duration',
+              keyExpression: { key: 'duration' },
               operator: new GraphQlEnumArgument(GraphQlOperatorType.LessThan),
               value: 100,
               type: new GraphQlEnumArgument(GraphQlFilterType.Attribute)
@@ -210,7 +210,7 @@ describe('Explore graphql query handler', () => {
           name: 'groupBy',
           value: {
             includeRest: true,
-            keys: ['serviceName'],
+            expressions: [{ key: 'serviceName' }],
             groupLimit: 2
           }
         },
@@ -219,7 +219,7 @@ describe('Explore graphql query handler', () => {
           value: [
             {
               direction: new GraphQlEnumArgument('ASC'),
-              key: 'duration',
+              keyExpression: { key: 'duration' },
               aggregation: new GraphQlEnumArgument(GraphQlMetricAggregationType.Average)
             }
           ]
@@ -233,14 +233,14 @@ describe('Explore graphql query handler', () => {
             {
               path: 'selection',
               alias: 'serviceName',
-              arguments: [{ name: 'key', value: 'serviceName' }],
+              arguments: [{ name: 'expression', value: { key: 'serviceName' } }],
               children: [{ path: 'value' }, { path: 'type' }]
             },
             {
               path: 'selection',
               alias: 'avg_duration',
               arguments: [
-                { name: 'key', value: 'duration' },
+                { name: 'expression', value: { key: 'duration' } },
                 { name: 'aggregation', value: new GraphQlEnumArgument(GraphQlMetricAggregationType.Average) }
               ],
               children: [{ path: 'value' }, { path: 'type' }]
@@ -249,7 +249,7 @@ describe('Explore graphql query handler', () => {
               path: 'selection',
               alias: 'avgrate_min_duration',
               arguments: [
-                { name: 'key', value: 'duration' },
+                { name: 'expression', value: { key: 'duration' } },
                 { name: 'aggregation', value: new GraphQlEnumArgument(GraphQlMetricAggregationType.Avgrate) },
                 { name: 'units', value: new GraphQlEnumArgument(GraphQlIntervalUnit.Minutes) },
                 { name: 'size', value: 1 }
diff --git a/projects/observability/src/shared/graphql/request/handlers/spans/span-graphql-query-handler.service.test.ts b/projects/observability/src/shared/graphql/request/handlers/spans/span-graphql-query-handler.service.test.ts
index a8216410d..60049401d 100644
--- a/projects/observability/src/shared/graphql/request/handlers/spans/span-graphql-query-handler.service.test.ts
+++ b/projects/observability/src/shared/graphql/request/handlers/spans/span-graphql-query-handler.service.test.ts
@@ -101,7 +101,7 @@ describe('SpanGraphQlQueryHandlerService', () => {
               operator: new GraphQlEnumArgument('EQUALS'),
               value: 'test-id',
               type: new GraphQlEnumArgument(GraphQlFilterType.Attribute),
-              key: 'id'
+              keyExpression: { key: 'id' }
             }
           ]
         }
@@ -111,8 +111,8 @@ describe('SpanGraphQlQueryHandlerService', () => {
           path: 'results',
           children: [
             { path: 'id' },
-            { path: 'attribute', alias: 'apiName', arguments: [{ name: 'key', value: 'apiName' }] },
-            { path: 'attribute', alias: 'duration', arguments: [{ name: 'key', value: 'duration' }] }
+            { path: 'attribute', alias: 'apiName', arguments: [{ name: 'expression', value: { key: 'apiName' } }] },
+            { path: 'attribute', alias: 'duration', arguments: [{ name: 'expression', value: { key: 'duration' } }] }
           ]
         },
         { path: 'total' }
@@ -145,7 +145,7 @@ describe('SpanGraphQlQueryHandlerService', () => {
               operator: new GraphQlEnumArgument('EQUALS'),
               value: 'test-id',
               type: new GraphQlEnumArgument(GraphQlFilterType.Attribute),
-              key: 'id'
+              keyExpression: { key: 'id' }
             }
           ]
         }
@@ -155,8 +155,8 @@ describe('SpanGraphQlQueryHandlerService', () => {
           path: 'results',
           children: [
             { path: 'id' },
-            { path: 'attribute', alias: 'apiName', arguments: [{ name: 'key', value: 'apiName' }] },
-            { path: 'attribute', alias: 'duration', arguments: [{ name: 'key', value: 'duration' }] }
+            { path: 'attribute', alias: 'apiName', arguments: [{ name: 'expression', value: { key: 'apiName' } }] },
+            { path: 'attribute', alias: 'duration', arguments: [{ name: 'expression', value: { key: 'duration' } }] }
           ]
         },
         { path: 'total' }
diff --git a/projects/observability/src/shared/graphql/request/handlers/spans/spans-graphql-query-handler.service.test.ts b/projects/observability/src/shared/graphql/request/handlers/spans/spans-graphql-query-handler.service.test.ts
index f91e6a988..dbb0a0cb1 100644
--- a/projects/observability/src/shared/graphql/request/handlers/spans/spans-graphql-query-handler.service.test.ts
+++ b/projects/observability/src/shared/graphql/request/handlers/spans/spans-graphql-query-handler.service.test.ts
@@ -97,7 +97,7 @@ describe('SpansGraphQlQueryHandlerService', () => {
               direction: {
                 value: 'ASC'
               },
-              key: 'apiName'
+              keyExpression: { key: 'apiName' }
             }
           ]
         }
@@ -109,22 +109,12 @@ describe('SpansGraphQlQueryHandlerService', () => {
             { path: 'id' },
             {
               alias: 'apiName',
-              arguments: [
-                {
-                  name: 'key',
-                  value: 'apiName'
-                }
-              ],
+              arguments: [{ name: 'expression', value: { key: 'apiName' } }],
               path: 'attribute'
             },
             {
               alias: 'duration',
-              arguments: [
-                {
-                  name: 'key',
-                  value: 'duration'
-                }
-              ],
+              arguments: [{ name: 'expression', value: { key: 'duration' } }],
               path: 'attribute'
             }
           ]
diff --git a/projects/observability/src/shared/graphql/request/handlers/traces/trace-graphql-query-handler.service.test.ts b/projects/observability/src/shared/graphql/request/handlers/traces/trace-graphql-query-handler.service.test.ts
index 4112f5846..a0a076ffd 100644
--- a/projects/observability/src/shared/graphql/request/handlers/traces/trace-graphql-query-handler.service.test.ts
+++ b/projects/observability/src/shared/graphql/request/handlers/traces/trace-graphql-query-handler.service.test.ts
@@ -79,7 +79,10 @@ describe('TraceGraphQlQueryHandlerService', () => {
       children: [
         {
           path: 'results',
-          children: [{ path: 'id' }, { path: 'attribute', alias: 'name', arguments: [{ name: 'key', value: 'name' }] }]
+          children: [
+            { path: 'id' },
+            { path: 'attribute', alias: 'name', arguments: [{ name: 'expression', value: { key: 'name' } }] }
+          ]
         }
       ]
     });
@@ -113,7 +116,10 @@ describe('TraceGraphQlQueryHandlerService', () => {
       children: [
         {
           path: 'results',
-          children: [{ path: 'id' }, { path: 'attribute', alias: 'name', arguments: [{ name: 'key', value: 'name' }] }]
+          children: [
+            { path: 'id' },
+            { path: 'attribute', alias: 'name', arguments: [{ name: 'expression', value: { key: 'name' } }] }
+          ]
         }
       ]
     });
@@ -156,7 +162,10 @@ describe('TraceGraphQlQueryHandlerService', () => {
       children: [
         {
           path: 'results',
-          children: [{ path: 'id' }, { path: 'attribute', alias: 'name', arguments: [{ name: 'key', value: 'name' }] }]
+          children: [
+            { path: 'id' },
+            { path: 'attribute', alias: 'name', arguments: [{ name: 'expression', value: { key: 'name' } }] }
+          ]
         }
       ]
     });
@@ -190,7 +199,10 @@ describe('TraceGraphQlQueryHandlerService', () => {
       children: [
         {
           path: 'results',
-          children: [{ path: 'id' }, { path: 'attribute', alias: 'name', arguments: [{ name: 'key', value: 'name' }] }]
+          children: [
+            { path: 'id' },
+            { path: 'attribute', alias: 'name', arguments: [{ name: 'expression', value: { key: 'name' } }] }
+          ]
         }
       ]
     });
diff --git a/projects/observability/src/shared/graphql/request/handlers/traces/traces-graphql-query-handler.service.test.ts b/projects/observability/src/shared/graphql/request/handlers/traces/traces-graphql-query-handler.service.test.ts
index a35a92502..a16752d56 100644
--- a/projects/observability/src/shared/graphql/request/handlers/traces/traces-graphql-query-handler.service.test.ts
+++ b/projects/observability/src/shared/graphql/request/handlers/traces/traces-graphql-query-handler.service.test.ts
@@ -74,12 +74,7 @@ describe('TracesGraphQlQueryHandlerService', () => {
             {
               alias: 'name',
               path: 'attribute',
-              arguments: [
-                {
-                  name: 'key',
-                  value: 'name'
-                }
-              ]
+              arguments: [{ name: 'expression', value: { key: 'name' } }]
             }
           ]
         },