diff --git a/.changeset/fluffy-actors-float.md b/.changeset/fluffy-actors-float.md
new file mode 100644
index 000000000000..b36ce1cf2f62
--- /dev/null
+++ b/.changeset/fluffy-actors-float.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+chore: more compact representation for invalidated search param
diff --git a/packages/kit/src/runtime/client/client.js b/packages/kit/src/runtime/client/client.js
index 0e05ded0a3a0..1ab1fce16087 100644
--- a/packages/kit/src/runtime/client/client.js
+++ b/packages/kit/src/runtime/client/client.js
@@ -33,7 +33,7 @@ import * as devalue from 'devalue';
 import { INDEX_KEY, PRELOAD_PRIORITIES, SCROLL_KEY, SNAPSHOT_KEY } from './constants.js';
 import { validate_common_exports } from '../../utils/exports.js';
 import { compact } from '../../utils/array.js';
-import { validate_depends } from '../shared.js';
+import { INVALIDATED_PARAM, validate_depends } from '../shared.js';
 
 let errored = false;
 
@@ -1772,13 +1772,10 @@ export function create_client(app, target) {
 async function load_data(url, invalid) {
 	const data_url = new URL(url);
 	data_url.pathname = add_data_suffix(url.pathname);
-	if (DEV && url.searchParams.has('x-sveltekit-invalidated')) {
-		throw new Error('Cannot used reserved query parameter "x-sveltekit-invalidated"');
+	if (DEV && url.searchParams.has(INVALIDATED_PARAM)) {
+		throw new Error(`Cannot used reserved query parameter "${INVALIDATED_PARAM}"`);
 	}
-	data_url.searchParams.append(
-		'x-sveltekit-invalidated',
-		invalid.map((x) => (x ? '1' : '')).join('_')
-	);
+	data_url.searchParams.append(INVALIDATED_PARAM, invalid.map((i) => (i ? '1' : '0')).join(''));
 
 	const res = await native_fetch(data_url.href);
 
diff --git a/packages/kit/src/runtime/server/data/index.js b/packages/kit/src/runtime/server/data/index.js
index 8d7b14851d83..1fbec114a26d 100644
--- a/packages/kit/src/runtime/server/data/index.js
+++ b/packages/kit/src/runtime/server/data/index.js
@@ -8,8 +8,6 @@ import { text } from '../../../exports/index.js';
 import * as devalue from 'devalue';
 import { create_async_iterator } from '../../../utils/streaming.js';
 
-export const INVALIDATED_PARAM = 'x-sveltekit-invalidated';
-
 const encoder = new TextEncoder();
 
 /**
diff --git a/packages/kit/src/runtime/server/respond.js b/packages/kit/src/runtime/server/respond.js
index ada5b05cf85e..ced8db6363fe 100644
--- a/packages/kit/src/runtime/server/respond.js
+++ b/packages/kit/src/runtime/server/respond.js
@@ -15,7 +15,7 @@ import {
 	strip_data_suffix
 } from '../../utils/url.js';
 import { exec } from '../../utils/routing.js';
-import { INVALIDATED_PARAM, redirect_json_response, render_data } from './data/index.js';
+import { redirect_json_response, render_data } from './data/index.js';
 import { add_cookies_to_headers, get_cookies } from './cookie.js';
 import { create_fetch } from './fetch.js';
 import { Redirect } from '../control.js';
@@ -27,6 +27,7 @@ import {
 import { get_option } from '../../utils/options.js';
 import { error, json, text } from '../../exports/index.js';
 import { action_json_redirect, is_action_json_request } from './page/actions.js';
+import { INVALIDATED_PARAM } from '../shared.js';
 
 /* global __SVELTEKIT_ADAPTER_NAME__ */
 
@@ -94,7 +95,10 @@ export async function respond(request, options, manifest, state) {
 	if (is_data_request) {
 		decoded = strip_data_suffix(decoded) || '/';
 		url.pathname = strip_data_suffix(url.pathname) || '/';
-		invalidated_data_nodes = url.searchParams.get(INVALIDATED_PARAM)?.split('_').map(Boolean);
+		invalidated_data_nodes = url.searchParams
+			.get(INVALIDATED_PARAM)
+			?.split('')
+			.map((node) => node === '1');
 		url.searchParams.delete(INVALIDATED_PARAM);
 	}
 
diff --git a/packages/kit/src/runtime/shared.js b/packages/kit/src/runtime/shared.js
index 563b081978f6..d8f60e7b71c9 100644
--- a/packages/kit/src/runtime/shared.js
+++ b/packages/kit/src/runtime/shared.js
@@ -10,3 +10,5 @@ export function validate_depends(route_id, dep) {
 		);
 	}
 }
+
+export const INVALIDATED_PARAM = 'x-sveltekit-invalidated';
diff --git a/packages/kit/test/apps/basics/test/client.test.js b/packages/kit/test/apps/basics/test/client.test.js
index 127f85dbed5b..efb305e6727d 100644
--- a/packages/kit/test/apps/basics/test/client.test.js
+++ b/packages/kit/test/apps/basics/test/client.test.js
@@ -24,7 +24,7 @@ test.describe('Caching', () => {
 		const [, response] = await Promise.all([
 			app.goto('/caching/server-data'),
 			page.waitForResponse((request) =>
-				request.url().endsWith('server-data/__data.json?x-sveltekit-invalidated=_1')
+				request.url().endsWith('server-data/__data.json?x-sveltekit-invalidated=01')
 			)
 		]);
 		expect(response.headers()['cache-control']).toBe('public, max-age=30');
diff --git a/packages/kit/test/apps/basics/test/cross-platform/test.js b/packages/kit/test/apps/basics/test/cross-platform/test.js
index fa2e3dd736f8..2042d5b42f29 100644
--- a/packages/kit/test/apps/basics/test/cross-platform/test.js
+++ b/packages/kit/test/apps/basics/test/cross-platform/test.js
@@ -595,7 +595,7 @@ test.describe('Redirects', () => {
 			const [, response] = await Promise.all([
 				app.goto('/redirect/in-handle?throw&cookies'),
 				page.waitForResponse((request) =>
-					request.url().endsWith('in-handle/__data.json?throw=&cookies=&x-sveltekit-invalidated=_1')
+					request.url().endsWith('in-handle/__data.json?throw=&cookies=&x-sveltekit-invalidated=01')
 				)
 			]);
 			expect((await response.allHeaders())['set-cookie']).toBeDefined();