Deploying Your FastAPI & Pydantic App

Learn how to deploy your FastAPI application, utilizing Pydantic for data validation, to Heroku for production use.

By Kevin McAleer,    3 Minutes

Preparing for Deployment

Deploying a FastAPI application involves several key steps to ensure your application is ready for production. This includes setting up a production server, ensuring your application is secure, and choosing the right hosting platform.

Requirements for Deployment

Before deploying, ensure your application:

• Is using a production-ready server like Uvicorn or Gunicorn.
• Has environment variables configured for any sensitive data.
• Includes a requirements.txt file with all the necessary Python packages.

Deploying to Heroku

Heroku is a cloud platform that simplifies the deployment process. Here’s a basic guide to deploying your FastAPI and Pydantic application to Heroku.

Step 1: Prepare Your Application

Make sure your application structure is ready for deployment. This includes organizing your application files, including a Procfile, which tells Heroku how to run your application.

Procfile

web: uvicorn main:app --host=0.0.0.0 --port=${PORT:-5000}

This Procfile instructs Heroku to start your FastAPI application with Uvicorn, binding to the port assigned by Heroku.

Step 2: Set Up Heroku

If you haven’t already, install the Heroku CLI and create a new Heroku app:

heroku login
heroku create your-app-name

Step 3: Deploy Your Application

Commit your code to a Git repository if you haven’t done so. Then, deploy your application to Heroku using Git:

git init
heroku git:remote -a your-app-name
git add .
git commit -am "Initial deploy"
git push heroku master

Step 4: Verify the Deployment

Once deployed, Heroku will provide a URL to access your application. Visit this URL to ensure your FastAPI application is running correctly.

Post-Deployment Considerations

After deploying, monitor your application’s performance and be prepared to scale your Heroku dynos according to the load. Additionally, consider setting up a continuous deployment pipeline for easier updates.

Lesson Assignment

Deploy a simple FastAPI application that includes Pydantic models for data validation to Heroku. Ensure your application is accessible via a public URL and test its endpoints to confirm they are functioning as expected in the production environment.

Additional Resources

• Heroku Documentation
• FastAPI Deployment
• Uvicorn Deployment