diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b31db58..547edd6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,57 +3,122 @@ name: Continuous Integration
 on:
     push:
         branches:
-            - develop
+            - main
         paths-ignore:
-            - 'README.md'
-            - 'docs/**'
-            - '.github/workflows/docs.yml'
-            - '.github/workflows/release.yml'
+            - "**.md"
+            - "renovate.json"
+            - ".github/ISSUE_TEMPLATE/**"
+            - ".github/PULL_REQUEST_TEMPLATE/**"
+            - ".github/workflows/docs.yml"
+            - ".github/workflows/release.yml"
     
     pull_request:
         paths-ignore:
-            - 'README.md'
-            - 'docs/**'
-            - '.github/workflows/docs.yml'
-            - '.github/workflows/release.yml'
-
+            - "**.md"
+            - "renovate.json"
+            - ".github/ISSUE_TEMPLATE/**"
+            - ".github/PULL_REQUEST_TEMPLATE/**"
+            - ".github/workflows/docs.yml"
+            - ".github/workflows/release.yml"
 concurrency:
     group: ${{ github.workflow }}-${{ github.ref }}
     cancel-in-progress: true
 
 jobs:
-    unit-tests:
-        name: Unit Tests
+    test-and-analysis:
+        name: Test & Analysis
         runs-on: ubuntu-latest
+        timeout-minutes: 30
+        permissions:
+            contents: read
         env:
-            GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-            SONAR_ORGANIZATION: ${{ secrets.SONAR_ORGANIZATION }}
-            SONAR_PROJECT_KEY: ${{ secrets.SONAR_PROJECT_KEY }}
             SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
+            SONAR_ANALYSIS: true
         
         steps:
-            -   name: Checkout
-                uses: actions/checkout@v6
-                with:
-                    fetch-depth: 0
-                    show-progress: false
-            -   name: Install .NET SDK
-                uses: actions/setup-dotnet@v5
-                with:
-                    global-json-file: global.json
-            -   name: NuGet Cache
-                uses: actions/cache@v5
-                with:
-                    path: ~/.nuget/packages
-                    key: ${{ runner.os}}-nuget-${{ hashFiles('**/packages.lock.json') }}
-                    restore-keys: ${{ runner.os }}-nuget
-            -   name: Test
-                run: ./build.sh Test
-            -   name: Publish Test Results
-                if: always()
-                uses: dorny/test-reporter@v2
-                with:
-                    name: Test Results
-                    path: .nuke/temp/TestResults/*.trx
-                    reporter: dotnet-trx
-                    path-replace-backslashes: true
+            - name: Checkout
+              uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+              with:
+                  fetch-depth: 0
+                  show-progress: false
+
+            - name: Setup .NET
+              uses: actions/setup-dotnet@c2fa09f4bde5ebb9d1777cf28262a3eb3db3ced7 # v5.2.0
+              with:
+                  global-json-file: global.json
+                  cache: true
+                  cache-dependency-path: '**/Directory.Packages.props'
+
+            - name: Restore dependencies
+              run: dotnet restore
+
+            - name: Install SonarCloud scanner
+              if: github.actor != 'dependabot[bot]' && github.actor != 'renovate[bot]'
+              run: dotnet tool update dotnet-sonarscanner --tool-path .sonar/scanner
+
+            - name: Begin SonarCloud analysis
+              if: github.actor != 'dependabot[bot]' && github.actor != 'renovate[bot]'
+              run: |
+                  .sonar/scanner/dotnet-sonarscanner begin \
+                    /k:"visus:AddressValidation" \
+                    /o:"visus" \
+                    /d:sonar.token="$SONAR_TOKEN" \
+                    /d:sonar.host.url="https://sonarcloud.io" \
+                    /d:sonar.cs.vscoveragexml.reportsPaths="**/TestResults/**/*.xml" \
+                    /d:sonar.cs.vstest.reportsPaths="**/TestResults/**/*.trx"
+
+            - name: Build
+              run: dotnet build -c Release --no-restore
+
+            - name: Run tests
+              run: |
+                  dotnet test -c Release --no-build --no-restore -- \
+                    --coverage \
+                    --coverage-output-format xml \
+                    --report-trx
+
+            - name: Upload test results
+              if: always()
+              uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+              with:
+                  name: test-results
+                  path: "**/TestResults/*.trx"
+                  retention-days: 1
+
+            - name: End SonarCloud analysis
+              if: github.actor != 'dependabot[bot]' && github.actor != 'renovate[bot]'
+              run: |
+                  .sonar/scanner/dotnet-sonarscanner end \
+                    /d:sonar.token="$SONAR_TOKEN"
+    
+    publish-test-results:
+        name: Publish Test Results
+        runs-on: ubuntu-latest
+        needs: test-and-analysis
+        if: always()
+        timeout-minutes: 10
+        permissions:
+            contents: read
+            checks: write
+            pull-requests: write
+        
+        steps:
+            - name: Checkout
+              uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+              with:
+                  fetch-depth: 1
+                  show-progress: false
+
+            - name: Download test results
+              uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
+              with:
+                  name: test-results
+                  path: test-results
+
+            - name: Publish test results
+              uses: dorny/test-reporter@df6247429542221bc30d46a036ee47af1102c451 # v2.7.0
+              with:
+                  name: Test Results
+                  path: test-results/**/*.trx
+                  reporter: dotnet-trx
+                  fail-on-error: false
diff --git a/src/Visus.AddressValidation.Integration.FedEx/Clients/FedExAddressValidationClient.cs b/src/Visus.AddressValidation.Integration.FedEx/Clients/FedExAddressValidationClient.cs
index cb8f6f9..714942c 100644
--- a/src/Visus.AddressValidation.Integration.FedEx/Clients/FedExAddressValidationClient.cs
+++ b/src/Visus.AddressValidation.Integration.FedEx/Clients/FedExAddressValidationClient.cs
@@ -36,7 +36,10 @@ public FedExAddressValidationClient(HttpClient httpClient, IOptions<FedExService
             httpRequest.Headers.Add("x-customer-transaction-id", request.CustomerTransactionId);
         }
 
-        httpRequest.Headers.Add("x-locale", _options.Value.Locale);
+        if ( !string.IsNullOrWhiteSpace(_options.Value.Locale) )
+        {
+            httpRequest.Headers.Add("x-locale", _options.Value.Locale);
+        }
 
         httpRequest.Content = JsonContent.Create(request, ApiRequestJsonSerializerContext.Default.ApiRequest);
 
diff --git a/src/Visus.AddressValidation.Integration.FedEx/Configuration/FedExServiceOptions.cs b/src/Visus.AddressValidation.Integration.FedEx/Configuration/FedExServiceOptions.cs
index bc3c074..5aea57a 100644
--- a/src/Visus.AddressValidation.Integration.FedEx/Configuration/FedExServiceOptions.cs
+++ b/src/Visus.AddressValidation.Integration.FedEx/Configuration/FedExServiceOptions.cs
@@ -1,7 +1,6 @@
 namespace Visus.AddressValidation.Integration.FedEx.Configuration;
 
 using System.ComponentModel.DataAnnotations;
-using System.Globalization;
 using AddressValidation.Abstractions;
 
 /// <summary>
@@ -81,12 +80,12 @@ public sealed class FedExServiceOptions : IValidatableObject
     ///     used for address validation responses returned by the FedEx API.
     /// </summary>
     /// <remarks>
-    ///     Defaults to <see cref="CultureInfo.CurrentCulture" />.<see cref="CultureInfo.Name" />
-    ///     of the executing thread at the time the options object is
-    ///     constructed. Use a value such as <c>en-US</c> or <c>fr-FR</c> to
+    ///     When <see langword="null" /> (the default), the <c>x-locale</c>
+    ///     request header is omitted and FedEx will use its own default locale.
+    ///     Set to an IETF BCP 47 tag such as <c>en-US</c> or <c>fr-FR</c> to
     ///     request responses in a specific language and region.
     /// </remarks>
-    public string Locale { get; set; } = CultureInfo.CurrentCulture.Name;
+    public string? Locale { get; set; }
 
     /// <summary>
     ///     Performs cross-property validation on the options object.
@@ -115,7 +114,7 @@ public IEnumerable<ValidationResult> Validate(ValidationContext validationContex
                 [nameof(EndpointOverrideUri),]);
         }
 
-        if ( !Constants.SupportedLocales.Contains(Locale) )
+        if ( Locale is not null && !Constants.SupportedLocales.Contains(Locale) )
         {
             yield return new ValidationResult(
                 $"'{Locale}' is not a supported IETF BCP 47 language tag.",
diff --git a/tests/Visus.AddressValidation.Integration.FedEx.Tests/ApiTests.PublicApi_HasNoBreakingChanges_Async.verified.txt b/tests/Visus.AddressValidation.Integration.FedEx.Tests/ApiTests.PublicApi_HasNoBreakingChanges_Async.verified.txt
index 961bc11..5fb2228 100644
--- a/tests/Visus.AddressValidation.Integration.FedEx.Tests/ApiTests.PublicApi_HasNoBreakingChanges_Async.verified.txt
+++ b/tests/Visus.AddressValidation.Integration.FedEx.Tests/ApiTests.PublicApi_HasNoBreakingChanges_Async.verified.txt
@@ -16,7 +16,7 @@ namespace Visus.AddressValidation.Integration.FedEx.Configuration
         public required string ClientSecret { get; set; }
         public System.Uri EndpointBaseUri { get; }
         public System.Uri? EndpointOverrideUri { get; set; }
-        public string Locale { get; set; }
+        public string? Locale { get; set; }
         public System.Collections.Generic.IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(System.ComponentModel.DataAnnotations.ValidationContext validationContext) { }
     }
     [Microsoft.Extensions.Options.OptionsValidator]
diff --git a/tests/Visus.AddressValidation.SourceGeneration.Tests/ApiTests.PublicApi_HasNoBreakingChanges_Async.verified.txt b/tests/Visus.AddressValidation.SourceGeneration.Tests/ApiTests.PublicApi_HasNoBreakingChanges_Async.verified.txt
new file mode 100644
index 0000000..1f4a88c
--- /dev/null
+++ b/tests/Visus.AddressValidation.SourceGeneration.Tests/ApiTests.PublicApi_HasNoBreakingChanges_Async.verified.txt
@@ -0,0 +1,12 @@
+[assembly: System.Resources.NeutralResourcesLanguage("en")]
+[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("DynamicProxyGenAssembly2")]
+[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("Visus.AddressValidation.SourceGeneration.Tests")]
+namespace Visus.AddressValidation.SourceGeneration
+{
+    [Microsoft.CodeAnalysis.Generator]
+    public sealed class CustomResponseDataGenerator : Microsoft.CodeAnalysis.IIncrementalGenerator
+    {
+        public CustomResponseDataGenerator() { }
+        public void Initialize(Microsoft.CodeAnalysis.IncrementalGeneratorInitializationContext context) { }
+    }
+}
\ No newline at end of file
diff --git a/tests/Visus.AddressValidation.SourceGeneration.Tests/ApiTests.cs b/tests/Visus.AddressValidation.SourceGeneration.Tests/ApiTests.cs
new file mode 100644
index 0000000..af8bade
--- /dev/null
+++ b/tests/Visus.AddressValidation.SourceGeneration.Tests/ApiTests.cs
@@ -0,0 +1,25 @@
+extern alias sourcegen;
+
+namespace Visus.AddressValidation.SourceGeneration.Tests;
+
+using System.Runtime.CompilerServices;
+using PublicApiGenerator;
+
+internal sealed class ApiTests
+{
+    [Test]
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public async Task PublicApi_HasNoBreakingChanges_Async()
+    {
+        string api = typeof(sourcegen::Visus.AddressValidation.SourceGeneration.CustomResponseDataGenerator).Assembly.GeneratePublicApi(new ApiGeneratorOptions
+        {
+            ExcludeAttributes =
+            [
+                "System.Reflection.AssemblyMetadataAttribute",
+                "System.Runtime.Versioning.TargetFrameworkAttribute",
+            ],
+        });
+
+        await Verify(api).ConfigureAwait(false);
+    }
+}
diff --git a/tests/Visus.AddressValidation.SourceGeneration.Tests/Visus.AddressValidation.SourceGeneration.Tests.csproj b/tests/Visus.AddressValidation.SourceGeneration.Tests/Visus.AddressValidation.SourceGeneration.Tests.csproj
index 8495712..dfc7a44 100644
--- a/tests/Visus.AddressValidation.SourceGeneration.Tests/Visus.AddressValidation.SourceGeneration.Tests.csproj
+++ b/tests/Visus.AddressValidation.SourceGeneration.Tests/Visus.AddressValidation.SourceGeneration.Tests.csproj
@@ -12,7 +12,7 @@
   <ItemGroup>
     <ProjectReference Include="..\..\src\Visus.AddressValidation.SourceGeneration\Visus.AddressValidation.SourceGeneration.csproj"
                       OutputItemType="Analyzer"
-                      ReferenceOutputAssembly="false"
+                      Aliases="sourcegen"
                       SetTargetFramework="targetframework=netstandard2.0"/>
     <ProjectReference Include="..\..\src\Visus.AddressValidation\Visus.AddressValidation.csproj"/>
   </ItemGroup>