FastAPI Tutorial for Beginners

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.7+ based on standard Python type hints. It is designed to be easy to use and to incorporate modern best practices in API development. In this tutorial, we will learn how to build a REST API with a JSON database using FastAPI.

Setting Up a Python Environment

Before we can start building our API with FastAPI, we need to make sure we have Python installed on our system. You can download Python from the official website and follow the installation instructions. Once Python is installed, we can proceed to install FastAPI and its dependencies using pip, the Python package manager.


$ pip install fastapi uvicorn


Creating a FastAPI Project

Now that we have FastAPI installed, we can create a new project by writing a simple Python script. We can start by creating a file called main.py and import FastAPI as follows:


from fastapi import FastAPI


We can then define our FastAPI app instance:


app = FastAPI()


Defining API Routes

With our FastAPI app instance created, we can now define our API routes using Python functions. Each route will correspond to a different endpoint in our API. Here’s an example of a simple “Hello, World!” route:


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


Running the FastAPI Application

After defining our API routes, we can run our FastAPI application using the Uvicorn server. We can start the server by running the following command in the terminal:


$ uvicorn main:app --reload


Once the server is running, we can access our API at http://localhost:8000. We can test our API endpoints using a tool like Postman or a web browser.

Building a REST API with a JSON Database

With the basics of FastAPI covered, we can now start building a REST API that interacts with a JSON database. We can use the built-in JSONResponse class provided by FastAPI to work with JSON data. We can also use Pydantic models to define the structure of our JSON data and perform data validation.

Conclusion

FastAPI is a powerful and easy-to-use web framework for building modern APIs with Python. In this tutorial, we learned how to create a basic FastAPI project, define API routes, and build a REST API with a JSON database. We also explored some of the key features of FastAPI, such as automatic interactive API documentation and data validation using Pydantic models. With its high performance and modern features, FastAPI is a great choice for building APIs with Python.