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Optimize Blazor WebAssembly performance with AOT compilation

8 Oct 20253 minutes to read

This article explains how to improve the performance of Blazor WebAssembly (WASM) Apps using Ahead-of-Time (AOT) compilation, including apps that use Syncfusion® Blazor components.

AOT Compilation Overview

Blazor WebAssembly Apps run entirely in the browser via WebAssembly. By default, the app’s .NET assemblies are downloaded and executed using a Just-In-Time (JIT) interpreter. Enabling AOT compilation converts .NET Intermediate Language (IL) into native WebAssembly at build time, which can provide significant performance gains.

Enable AOT Compilation

Follow these steps to configure AOT for a Blazor WebAssembly App.

Prerequisites: Target .NET 8 or later and publish in Release configuration.

Step 1: Target .NET 8+

Ensure your project targets .NET 8 or later:

<TargetFramework>net8.0</TargetFramework>

Step 2: Enable AOT in your project file

Add the following to your .csproj file:

<PropertyGroup>
  <RunAOTCompilation>true</RunAOTCompilation>
</PropertyGroup>

Then publish the project using:

dotnet publish -c Release

The output will be located in:

bin/Release/net8.0/publish/wwwroot/

AOT improves performance but increases WASM size (~1.5–2×). Use Brotli compression and proper caching to minimize impact.

Size vs Performance Tradeoff

The following sample metrics compare performance and size for Blazor WebAssembly with and without AOT, using a Syncfusion® Grid with paging enabled.

Metric Without AOT With AOT
Initial Load Time ~3.90 seconds ~3.04 seconds
On Page Refresh ~71 ms ~61 ms
Bundle Size (Brotli) ~114 MB ~192 MB
Memory Usage Slightly lower Slightly higher

AOT compilation increases app size but can significantly improve load time, interactivity, and overall runtime performance in Blazor WebAssembly apps.

Limitations

  • Longer build time: compared to standard builds.
  • Increased bundle size: Final WebAssembly size is larger.
  • Higher memory usage: While AOT improves performance, it may result in slightly higher memory usage at runtime due to native code execution.
  • Reduced flexibility: Dynamic features (e.g., reflection) may require additional handling.
  • More complex debugging: Source map support is limited.
  • Slower iterations: Any code change needs full rebuild, affecting dev productivity.

Considerations

  • Better performance: Native WebAssembly improves execution speed and UI responsiveness.
  • Enhanced security: Native code is harder to reverse-engineer than Intermediate Language code.
  • Cross-platform consistency: Consistent behavior across browsers and devices.

Specific Recommendations

To further reduce published output size, enable linker and trimming options in the .csproj.

<PublishTrimmed>true</PublishTrimmed>
<InvariantGlobalization>true</InvariantGlobalization>
<BlazorWebAssemblyEnableLinking>true</BlazorWebAssemblyEnableLinking>

InvariantGlobalization reduces globalization data. Only use this if your app doesn’t rely on specific culture or regional formats.