By default, Blazor WASM uses an **Interpreter** to run your code. AOT Compilation compiles your C# directly into WebAssembly machine code for maximum speed.
The interpreter is great for small apps, but it struggles with CPU-intensive tasks like image processing, complex math, or large-scale data manipulation. AOT can make these operations **10x to 20x faster**. It transforms your C# into high-performance binary that the browser executes almost natively.
There is no free lunch. AOT compilation significantly increases the size of your download bundle (often by 2x or 3x) because it includes the compiled machine code for all your logic. This leads to slower initial load times but much faster runtime performance.
Q: "When is AOT worth it?"
Architect Answer: "Use AOT only if your app has heavy computational requirements that make the UI feel sluggish. For standard 'Form-and-Data' enterprise apps, the Interpreter is usually fast enough, and the smaller download size is a better trade-off for the user's experience. Test your app's performance before committing to the extra payload of AOT."