Blazor Basics: WebAssembly Ahead-of-Time AOT Compilation

LocalStorage works for simple flags or small settings, but it’s synchronous, size-limited, and unsuitable for structured or transactional data. For apps that must remain interactive offline—even when relying on external endpoints—you can layer in custom caching logic. This gives basic offline capability for the shell of the application.

1.1 How AOT Works: Trading Download Size for Runtime Speed

The developer doesn’t need to use language-specific bindings for the common APIs included in WASI P2—they can simply compile a component and move on. Our goal here is to get a feel for the “idiomatic” development experience that is possible when a language toolchain supports native WASI P2 compilation. At the moment, componentize-dotnet only works on Windows. If you’re a Visual Studio Code user, you may also want to install the C# Dev Kit extension, but in this walkthrough, we’ll stick to the command line. The NativeAOT-LLVM compiler supports WASI P2 (with both .NET 8 and 9), giving developers native WASI P2 support. Building WebAssembly components in .NET/C# is easier than ever before.

First of all, enabling AOT compilation will increase the overall size of your application, since the compiled WebAssembly code isn’t as compact as the .NET IL (Intermediate Language) instructions. Enabling AOT compilation converts .NET Intermediate Language (IL) into native WebAssembly at build time, which can provide significant performance gains. Production Blazor WebAssembly applications need continuous performance validation to prevent regressions.

Production WebAssembly with Blazor: WASM Performance Optimization, AOT Compilation, and Offline-First PWAs

These observations directly inform optimizations covered in earlier sections—like applying virtualization, using @key, trimming heavy dependencies, or enabling SIMD. The Performance panel in modern browsers captures WebAssembly call stacks alongside JavaScript and rendering activity. This section focuses on practical tools and workflows that integrate naturally with the patterns already established in this article. Profiling reveals slow paths, benchmarking quantifies improvements, and CI/CD pipelines enforce performance budgets.

• Turning your Blazor application into a PWA adds capabilities such as installation prompts, offline caching, and background updates.
• Instead of interpreting IL at runtime, the browser executes native WebAssembly instructions.
• This may take a while depending on the size and complexity of your application.
• Choosing between them depends on expected load behavior, deployment strategy, and performance constraints.

AOT compilation results in runtime performance improvements at the expense of a larger app size. This article describes the build tools for standalone Blazor WebAssembly apps and how to compile an app ahead of deployment with ahead-of-time (AOT) compilation. Blazor WebAssembly is a high-performance .NET framework for building web apps. Note.NET WebAssembly build tools for .NET 6 projectsThe wasm-tools workload installs the build tools for the latest release. Although the article primarily focuses on standalone Blazor WebAssembly apps, the section on heap size for some mobile device browsers also applies to the client-side project (.Client) of a Blazor Web App. Join us on the wasmCloud Slack to connect with the sweepstakes casino community, keep up with or get involved in the project, and chat with other developers building components across language ecosystems.