README.md

FastAPI + Wasmer

This example shows how to run a minimal FastAPI app on Wasmer Edge.

Demo

https://fastapi-template.wasmer.app/

How it Works

Your FastAPI application exposes a module-level ASGI application named app in main.py:

# main.py
from fastapi import FastAPI

app = FastAPI()

@app.get("/")
async def root():
    return {"message": "Hello World"}

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)

Key points:

• The app variable is the ASGI application that Wasmer Edge runs (e.g., main:app).
• A single GET / route returns JSON: {"message": "Hello World"}.
• When executed directly (python main.py), it serves via Uvicorn on port 8000.

This example uses ASGI with FastAPI to handle requests on Wasmer Edge.

Running Locally

Choose one of the following:

# Option 1: Run the file directly (uses the __main__ block)
python main.py

# Option 2: Use uvicorn explicitly
uvicorn main:app --host 0.0.0.0 --port 8000 --reload

Your FastAPI application is now available at http://localhost:8000.

Routing Overview

• GET / → returns:

  { "message": "Hello World" }

Deploying to Wasmer (Overview)

1. Ensure your project exposes main:app.
2. Deploy to Wasmer
3. Visit https://<your-subdomain>.wasmer.app/ to test.

Tip: Keep the app entrypoint as main:app (module:variable) so the platform can discover it easily.