How to Upgrade Your Blazor WebAssembly App to .NET 10 for Enhanced Performance

What You Need

• .NET 10 SDK – Download from dotnet.microsoft.com
• Existing Blazor WebAssembly app (preferably on .NET 8)
• Code editor (Visual Studio 2022+, VS Code, or Rider)
• Familiarity with .csproj files and NuGet
• Optional: CDN or static hosting for deploying updated assets

Step 1: Update Your Development Environment

Start by installing the .NET 10 SDK. This gives you the latest compiler, runtime, and tooling needed to build WebAssembly applications targeting .NET 10. After installation, verify with dotnet --version. You should see 10.x.x.

Step 2: Update the Target Framework

Open your project’s .csproj file. Change the <TargetFramework> from net8.0 (or earlier) to net10.0 for WebAssembly projects. The line should look like this:

<TargetFramework>net10.0</TargetFramework>

If you have multiple projects (e.g., a shared library), update all of them to net10.0.

Step 3: Update NuGet Packages

Right-click the solution and select Manage NuGet Packages for Solution. Update all packages that reference .NET or Blazor libraries to versions compatible with .NET 10. Pay special attention to:

• Microsoft.AspNetCore.Components.WebAssembly
• Microsoft.AspNetCore.Components.WebAssembly.DevServer
• Microsoft.NET.Sdk.WebAssembly.Pack

Run dotnet restore to ensure all dependencies resolve correctly.

Step 4: Remove Custom Fingerprinting Scripts (If Any)

.NET 10 automatically fingerprints WebAssembly assets. If you previously used a custom script (PowerShell or other) to rename files with SHA256 hashes and pass integrity arguments from JavaScript, you can now delete it. The blazor.boot.json manifest still exists, but filenames now include a unique identifier. Also remove any manual integrity checks in your dotnet.js initialization code.

Tip: If you load the .NET WASM runtime inside a WebWorker, set dotnetSidecar = true when initializing to ensure proper startup.

Step 5: Enable AOT and Leverage WasmStripILAfterAOT

For ahead-of-time compilation, add <RunAOTCompilation>true</RunAOTCompilation> to your .csproj under a <PropertyGroup>. In .NET 10, <WasmStripILAfterAOT>true</WasmStripILAfterAOT> is the default, so you don’t need to set it explicitly. However, if you had set it to false previously, remove that line to take advantage of the smaller output. The IL for AOT-compiled methods is stripped automatically, reducing the download size.

Note: If you use a hybrid JIT+AOT packaging strategy (like Copilot Studio), be aware that stripping IL makes AOT assemblies different from JIT versions. Files that are identical can still be deduplicated, but verify your custom packaging scripts handle the mismatch.

Step 6: Rebuild and Test Locally

Run dotnet build or build from your IDE. If you enabled AOT, expect a longer first build (WebAssembly compilation). After building, launch the app locally using dotnet run or the IDE debugger. Verify:

• All pages load correctly
• Interactive components work
• Network requests for .wasm and .dll files use the new fingerprinted filenames
• No console errors about missing or invalid integrity values

Step 7: Update Deployment Pipeline

Because fingerprints are now automatic, you may need to update your CI/CD scripts. Ensure your hosting environment (Azure Static Web Apps, GitHub Pages, etc.) can handle fingerprinted files and that caching headers use the new unique URLs. Remove any custom steps that renamed assets.

Step 8: Deploy to Production

Deploy the built wwwroot folder to your production server. The .NET 10 WASM runtime will serve assets with built-in cache busting and integrity validation. Monitor performance metrics to confirm faster startup times and reduced download sizes.

Conclusion & Tips

• Test thoroughly: .NET 10 is the latest version; ensure all third-party libraries are compatible.
• Use Blazor WebAssembly debugging in Chromium browsers to diagnose any issues.
• Consider enabling Brotli compression for .wasm files to further reduce size.
• If you use Web Workers, set dotnetSidecar as mentioned.
• Review your custom NPM packages if you bundle both JIT and AOT engines – the non-stripped IL used to allow deduplication; now you may need to adjust your factorization.

With these steps, your Blazor WebAssembly app will run on .NET 10, benefiting from automatic fingerprinting and smaller AOT outputs – just like Microsoft Copilot Studio. The upgrade is straightforward and immediately improves loading and caching.