FastAPI Boilerplate

FastAPI Boilerplate is a Vercel example that deploys Python FastAPI applications to Vercel's Serverless Functions using the ASGI interface, with one-click deployment and a live demo.

What is the FastAPI Boilerplate?

The FastAPI Boilerplate is a starter template from Vercel's official examples collection that demonstrates how to use the Python Runtime on Vercel with the FastAPI web framework. It takes a FastAPI application written in Python and deploys it as a serverless function, producing a publicly accessible URL for handling HTTP requests. The template is maintained by Vercel and is part of the vercel/examples GitHub repository, which currently has over 5,100 stars. A live demo of the deployed application is available at https://vercel-plus-fastapi.vercel.app/.

Key Features

• One-click deploy — A "Deploy with Vercel" button clones the repository into a new Vercel project with pre-filled demo title, description, and URL parameters.
• ASGI integration — Uses the Asynchronous Server Gateway Interface to allow FastAPI to handle asynchronous requests on Vercel's Python runtime.
• Local development — Run npm i -g vercel to install the Vercel CLI, then vercel dev to serve the application locally at http://localhost:3000.
• Official example — Provided by Vercel in their curated examples collection, which includes patterns for building robust and scalable applications.
• Demo URL — The deployed app at https://vercel-plus-fastapi.vercel.app/ lets you test the behavior of the boilerplate without deploying anything.

Who is it for?

• Python developers who want to deploy FastAPI backends without managing their own servers.
• Serverless practitioners looking for a reference pattern to run ASGI applications on Vercel.
• Teams already using Vercel that need a minimal, working FastAPI deployment to extend with their own endpoints.

What can you do with the FastAPI Boilerplate?

• Deploy APIs quickly: Use the one-click deploy button to get a live FastAPI endpoint in under a minute, then customize the Python code and redeploy.
• Test serverless behavior locally: Run vercel dev to emulate Vercel's serverless function environment on your machine before pushing changes.
• Learn from a working example: Study the small codebase to understand how Vercel wires up the Python runtime with ASGI for your own projects.

How does it work?

The template wires FastAPI to Vercel's Python runtime through ASGI, letting each HTTP request be handled as a serverless function invocation. Vercel detects the ASGI application and routes traffic to it. For local testing, the Vercel CLI's vercel dev command recreates the production serving environment, so you can develop without deploying.

FAQ

Is the FastAPI Boilerplate free to use?

The example code is open source in Vercel's GitHub repository, so you can copy and modify it without a license fee. Deploying it on Vercel is subject to your Vercel plan; usage within the free tier is possible, but larger workloads may require a paid plan.

How do I deploy the FastAPI app with one click?

Click the "Deploy with Vercel" button in the README or use the provided URL. It opens a Vercel project creation flow with the repository URL, demo title, description, and demo URL pre-filled, then you confirm and deploy.

Can I run this FastAPI example locally?

Yes. Install the Vercel CLI globally with npm i -g vercel, then run vercel dev inside the project directory. The app becomes available at http://localhost:3000, with hot reloading for code changes.

What Python runtime does Vercel use for this template?

Vercel's Serverless Functions support a Python runtime. This template uses ASGI with FastAPI, so Vercel's Python runtime handles the ASGI bridge and forwards requests to your FastAPI application.