Create a REST API in 15 Minutes with Python FastAPI Tutorial

FastAPI is a modern, fast (high-performance), web framework used for building APIs in Python with minimal code. In this tutorial, we will walk through how to create a basic REST API using FastAPI in just 15 minutes.

Step 1: Setup the Environment

First, you will need to have Python installed on your machine. You can check if you have it installed by running the following command in your terminal:

python --version

If you don’t have Python installed, you can download and install it from the official Python website.

Next, you will need to install FastAPI and Uvicorn, a lightning-fast ASGI server which will run our FastAPI application. You can install them using pip:

pip install fastapi uvicorn

Step 2: Create the FastAPI Application

Create a new Python file named main.py and open it in your favorite code editor. In this file, we will define our FastAPI application and endpoints.

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"message": "Hello, World!"}

This code creates a FastAPI application with one endpoint that returns a simple message when you access the root of the API.

Step 3: Start the FastAPI Application

To start the FastAPI application, run the following command in your terminal:

uvicorn main:app --reload

This command tells Uvicorn to run the FastAPI application defined in the main.py file. The --reload flag enables auto-reloading, which means the server will restart automatically when you make changes to your code.

Step 4: Test the API

Once you have started the FastAPI application, you can open a web browser and navigate to http://127.0.0.1:8000/ to see the message "Hello, World!" displayed.

You can also test the API using cURL or a tool like Postman. For example, to make a GET request to the root endpoint, run the following command in your terminal:

curl http://127.0.0.1:8000/

Step 5: Add More Endpoints

Now that you have a basic FastAPI application up and running, you can add more endpoints to create a more robust API. Here’s an example of adding a new endpoint that accepts a name parameter and returns a personalized message:

@app.get("/hello/{name}")
def say_hello(name: str):
    return {"message": f"Hello, {name}!"}

With this endpoint, you can now make a GET request to http://127.0.0.1:8000/hello/John and receive a response containing the message "Hello, John!".

Step 6: Deploy the API

Once you have finished building and testing your FastAPI application locally, you can deploy it to a server so that it can be accessed by others. There are many hosting options available for Python applications, such as Heroku, AWS, and Google Cloud.

To deploy your FastAPI application, you will need to package your code and dependencies, set up the server environment, and run the application using a production-grade server like Gunicorn.

Conclusion

In this tutorial, we have covered the basics of creating a REST API using FastAPI in Python. FastAPI is a powerful and efficient web framework that makes it easy to build APIs with minimal code while providing high performance and robustness.

By following this tutorial, you should now have a good understanding of how to create a basic FastAPI application, define endpoints, and test the API. You can continue to explore FastAPI’s features and build more complex APIs to suit your specific use case.