diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4eae014..5b8782b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,8 +32,14 @@ jobs:
       - name: Build
         run: dotnet build AzureExtensions.Functions.OpenApi.slnx -c Release --no-restore
 
-      - name: Test
-        run: dotnet test --solution AzureExtensions.Functions.OpenApi.slnx -c Release --no-build
+      - name: Test net8.0
+        run: dotnet test tests/AzureExtensions.Functions.OpenApi.Tests/AzureExtensions.Functions.OpenApi.Tests.csproj -f net8.0 -c Release --no-build
+
+      - name: Test net9.0
+        run: dotnet test tests/AzureExtensions.Functions.OpenApi.Tests/AzureExtensions.Functions.OpenApi.Tests.csproj -f net9.0 -c Release --no-build
+
+      - name: Test net10.0
+        run: dotnet test tests/AzureExtensions.Functions.OpenApi.Tests/AzureExtensions.Functions.OpenApi.Tests.csproj -f net10.0 -c Release --no-build
 
       - name: Pack
         run: dotnet pack src/AzureExtensions.Functions.OpenApi/AzureExtensions.Functions.OpenApi.csproj -c Release --no-build -o artifacts
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index bcf3397..6cccf86 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -8,7 +8,7 @@ By participating, you agree to abide by our [Code of Conduct](CODE_OF_CONDUCT.md
 
 ## Prerequisites
 
-- [.NET 10 SDK](https://dotnet.microsoft.com/download) (see [`global.json`](global.json) for the pinned version)
+- [.NET 10 SDK](https://dotnet.microsoft.com/download) (see [`global.json`](global.json) for the pinned version; the sample app still targets .NET 10, while the package targets .NET 8/.NET 9/.NET 10)
 - Git
 
 ## Getting started
@@ -59,7 +59,7 @@ This repo uses a **dev-first** flow:
 ## Coding conventions
 
 - Target framework and language settings follow the existing projects
-  (`net10.0`, nullable enabled, implicit usings).
+  (`net8.0;net9.0;net10.0` for the library/tests, `net10.0` for the sample app, nullable enabled, implicit usings).
 - Match the surrounding code style; keep changes surgical and avoid unrelated churn.
 - Prefer attribute-driven metadata for OpenAPI surface, consistent with the current design.
 
diff --git a/README.md b/README.md
index 972d7f3..6a55585 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 [![CI](https://github.com/Doomblaster/AzureExtensions.Functions.OpenApi/actions/workflows/ci.yml/badge.svg)](https://github.com/Doomblaster/AzureExtensions.Functions.OpenApi/actions/workflows/ci.yml)
 [![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE)
 
-A reusable .NET 10 class library that adds an **OpenAPI 3.x document endpoint** to an
+A reusable .NET class library for **.NET 8, .NET 9, and .NET 10** that adds an **OpenAPI 3.x document endpoint** to an
 [Azure Functions isolated worker (v4)](https://learn.microsoft.com/azure/azure-functions/dotnet-isolated-process-guide)
 app. Reference the package, call one registration method, and your app exposes an OpenAPI
 specification over HTTP that reflects its **real API**.
@@ -626,7 +626,7 @@ samples/SampleFunctionApp/        # isolated worker v4 sample consumer
 dotnet build AzureExtensions.Functions.OpenApi.slnx
 ```
 
-Requires the .NET 10 SDK.
+Building the full repo requires the .NET 10 SDK. The published package targets .NET 8, .NET 9, and .NET 10.
 
 ## Contributing
 
diff --git a/src/AzureExtensions.Functions.OpenApi/AzureExtensions.Functions.OpenApi.csproj b/src/AzureExtensions.Functions.OpenApi/AzureExtensions.Functions.OpenApi.csproj
index d74e17b..7d2ed49 100644
--- a/src/AzureExtensions.Functions.OpenApi/AzureExtensions.Functions.OpenApi.csproj
+++ b/src/AzureExtensions.Functions.OpenApi/AzureExtensions.Functions.OpenApi.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net10.0</TargetFramework>
+    <TargetFrameworks>net8.0;net9.0;net10.0</TargetFrameworks>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <LangVersion>latest</LangVersion>
diff --git a/tests/AzureExtensions.Functions.OpenApi.Tests/AzureExtensions.Functions.OpenApi.Tests.csproj b/tests/AzureExtensions.Functions.OpenApi.Tests/AzureExtensions.Functions.OpenApi.Tests.csproj
index 387d9e4..c1862ce 100644
--- a/tests/AzureExtensions.Functions.OpenApi.Tests/AzureExtensions.Functions.OpenApi.Tests.csproj
+++ b/tests/AzureExtensions.Functions.OpenApi.Tests/AzureExtensions.Functions.OpenApi.Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net10.0</TargetFramework>
+    <TargetFrameworks>net8.0;net9.0;net10.0</TargetFrameworks>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <LangVersion>latest</LangVersion>