diff --git a/Gemfile b/Gemfile
index ecfe332..28e5797 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,6 +5,7 @@ source "https://rubygems.org"
 # Specify your gem's dependencies in suma.gemspec
 gemspec
 
+gem "canon"
 gem "lutaml-model", github: "lutaml/lutaml-model", branch: "main"
 gem "nokogiri"
 gem "rake"
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 830810e..eacaabf 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -16,7 +16,7 @@
 end
 
 require "yaml"
-require "diffy"
+require "canon"
 
 # Define a helper method for capturing standard output/error
 def capture_output
@@ -31,37 +31,6 @@ def capture_output
   $stderr = original_stderr
 end
 
-RSpec::Matchers.define :be_yaml_equivalent_to do |expected|
-  match do |actual|
-    @actual_sorted = sort_yaml_keys(YAML.safe_load(actual)).to_yaml
-    @expected_sorted = sort_yaml_keys(YAML.safe_load(expected)).to_yaml
-    @actual_sorted == @expected_sorted
-  end
-
-  def sort_yaml_keys(obj)
-    case obj
-    when Hash
-      obj.transform_values { |v| sort_yaml_keys(v) }
-        .sort.to_h
-    when Array
-      obj.map { |item| sort_yaml_keys(item) }
-    else
-      obj
-    end
-  end
-
-  failure_message do |_actual|
-    diff = Diffy::Diff.new(@expected_sorted, @actual_sorted,
-                           include_diff_info: false,
-                           include_plus_and_minus_in_html: true,
-                           diff_options: "-u")
-
-    "expected YAML to be equivalent\n\n" \
-    "Diff:\n" +
-      diff.to_s(:color)
-  end
-end
-
 # Configure LutaML adapters
 Lutaml::Model::Config.configure do |config|
   config.xml_adapter_type = :nokogiri
diff --git a/unitsdb.gemspec b/unitsdb.gemspec
index a9ad54c..b31337a 100644
--- a/unitsdb.gemspec
+++ b/unitsdb.gemspec
@@ -31,7 +31,6 @@ Gem::Specification.new do |spec|
   spec.executables = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_dependency "diffy"
   spec.add_dependency "fuzzy_match"
   spec.add_dependency "lutaml-model", "~> 0.8.0"
   spec.add_dependency "rdf", "~> 3.1"