I deployed a .NET application that starts in 12 milliseconds, uses 8MB of memory, and runs faster than the equivalent Node.js version

Last weekend (9th of August), I did something that would have been impossible two years ago.

I deployed a .NET application that starts in 12 milliseconds, uses 8MB of memory, and runs faster than the equivalent Node.js version

Yes you heard me right… let me repeat

I DEPLOYED A .NET APPLICATION THAT STARTS IN 12 MILLISECONDS, USES 8MB OF MEMORY, AND RUNS FASTER THAN THE EQUIVALENT NODE.JS VERSION!!

— as a standalone WebAssembly binary.

.NET 9 combined WebAssembly (WASM) with Ahead-of-Time (AOT) compilation in a way that fundamentally shifts the performance equation. .NET applications can run anywhere with startup times that make Node.js look glitchy! ewww

BEWARE — I’m not talking about replacing Node.js everywhere. But for specific scenarios — serverless functions, edge computing, browser applications — this combination creates performance characteristics that Node.js simply can’t match

Let me show you exactly what I found —

🔻WASM + AOT

.NET applications to be honest sometime feels full of lag sometime — they need a runtime, they have slower cold starts, and they use more memory than lightweight alternatives like Node.js.

WASM + AOT eliminates all three problems.

Simplifying —

AOT compilation takes your .NET code and compiles it directly to native machine code before deployment. No Just-In-Time compilation, no runtime overhead. Then WebAssembly packages that compiled code into a format that can run anywhere — browsers, servers, edge devices.

I tested this with a simple API that processes financial data. Same logic, same algorithms, deployed three different ways —

Node.js version was winning until that last comparison💀 . Suddenly, .NET was dramatically High, Stoned and on fire!

🔻Understanding WASM + AOT in 1 Minute

It’s about making .NET deployable in places where it was never practical before.

Take serverless functions. With traditional .NET, cold starts kill performance. By the time your application loads the runtime and JIT-compiles your code, a Node.js function has already finished and returned a response.

But WASM + AOT flips this completely. Your .NET code is already compiled to native machine code and packaged in a tiny binary. No runtime to load, no compilation step, no warm-up period. Just instant execution.

I deployed the same portfolio calculation function to AWS Lambda in both Node.js and .NET 9 WASM:

Cold start is a way powerful when its about WASM + AOT

For applications that don’t maintain constant traffic, this makes .NET competitive in scenarios where it was previously unusable.

🔻How to Start Building WASM + AOT Applications

Just tell .NET to compile your application ahead of time and package it as WebAssembly instead of a regular executable. that’s it


  
    net9.0
    true
    wasm-wasi
    Exe
    true

🔻Where WASM + AOT Wins

Check this —

Best Fit for

  • Serverless functions with unpredictable traffic
  • Edge computing applications
  • Browser-based tools and calculators
  • Microservices with fast startup requirements
  • Applications deployed to resource-constrained environments

Red flag

  • Long-running applications that benefit from JIT optimizations over time
  • Applications requiring extensive .NET framework features
  • Complex enterprise applications with heavy dependency chains
  • Applications that need dynamic code generation or reflection

In my application(stock portfolio management), I split the architecture. The main portfolio management system runs on traditional .NET for maximum feature richness. But the real-time risk calculation API runs on WASM + AOT for instant response times.

💡End Note

This feels similar to when Docker changed how we think about application deployment, or when cloud computing changed how we think about infrastructure.

WASM + AOT makes .NET deployable in entirely new contexts.

Thank you 🖤