Building and Deploying FastAPI Applications to Vercel
When it comes to bringing your application to life, the final step is often the most crucial: deployment. With numerous tools at your disposal, choosing the right one can be overwhelming. In this article, we’ll explore how to deploy FastAPI applications to Vercel, a popular cloud hosting platform.
Getting Started with FastAPI
FastAPI is a modern, fast, and powerful Python web framework for building backend API applications. It boasts an impressive set of features, including API documentation powered by Swagger, security modules, and type checking to ensure code correctness. To follow along, you’ll need a basic understanding of Python, Git, and a Postman or virtualenv installation on your machine. Additionally, create a Vercel account to deploy your application.
Building a Simple Notes App
To demonstrate the deployment process, we’ll build a simple notes app. Start by creating a project folder and installing the necessary dependencies using virtualenv. Next, activate the virtual environment and install FastAPI and Uvicorn, an ASGI server that enables us to run our application.
Defining the Model Schema
In the model.py file, define a Pydantic schema called NoteSchema, which represents how notes data will be stored in our application’s temporary database. This schema will guide users when sending requests from the interactive docs.
Defining Routes for CRUD Operations
In the routes.py file, create an in-app database to store and retrieve notes, and import the NoteSchema. Define routes for GET requests, including a route to return all available notes and a route to return a note with a matching ID.
Testing Routes
Test the routes using Postman or Insomnia, sending GET requests to retrieve notes and POST requests to add new notes. Define update and delete routes, performing partial updates and deleting notes only if they exist.
Deploying to Vercel
To deploy your application to Vercel, create a vercel.json configuration file and add the necessary JSON code. This file specifies the path to the application’s entry point and the package to use when building the app. Create a requirements.txt file containing your application dependencies and initialize Vercel using the command line tool.
Previewing the Deployed Application
Follow the prompts in the console, and you’ll see a similar screen indicating a successful deployment. Preview the deployed application by clicking the links in the console or from your Vercel dashboard.
What’s Next?
In this article, we’ve learned how to build and deploy a FastAPI application to Vercel. To dive deeper into FastAPI, explore the official documentation and access the code used in this article on GitHub.