Real Python: Build a URL Shortener With FastAPI and Python

In this tutorial, you’ll build a URL shortener with Python and FastAPI. URLs can be extremely long and not user-friendly. This is where a URL shortener can come in handy. A URL shortener reduces the number of characters in a URL, making it easier to read, remember, and share.

By following this step-by-step project, you’ll build a URL shortener with Python and FastAPI. At the end of this tutorial, you’ll have a fully functional API-driven web app that creates shortened URLs that forward to target URLs.

In this tutorial, you’ll learn how to:

• Create a REST API with FastAPI
• Run a development web server with Uvicorn
• Model an SQLite database
• Investigate the auto-generated API documentation
• Interact with the database with CRUD actions
• Optimize your app by refactoring your code

This URL shortener project is for intermediate Python programmers who want to try out FastAPI and learn about API design, CRUD, and interaction with a database. To follow along, it’ll help if you’re familiar with the basics of handling HTTP requests. If you need a refresher on FastAPI, Using FastAPI to Build Python Web APIs is a great introduction.

Demo: Your Python URL Shortener

In this step-by-step project, you’ll build an API to create and manage shortened URLs. The main purpose of this API is to receive a full target URL and return a shortened URL. To try out your API endpoints, you’ll leverage the documentation that FastAPI automatically creates:

When you post a target URL to the URL shortener app, you get a shortened URL and a secret key back. The shortened URL contains a random key that forwards to the target URL. You can use the secret key to see the shortened URL’s statistics or delete the forwarding.

Project Overview

Your URL shortener Python project will provide API endpoints that are capable of receiving different HTTP request types. Each endpoint will perform an action that you’ll specify. Here’s a summary of your URL shortener’s API endpoints:

The code you’ll write in this tutorial focuses on getting the app working first. However, having a working app doesn’t always mean that the code behind it is perfect. That’s why you’ll find a step in this tutorial where you’ll refactor parts of your app.

If you want to have a look at the final source code, go ahead and download it:

This project is a great starting point to extend your API with more functionality. At the end of this tutorial, you’ll find ideas about what to build next.

Prerequisites

To get the most out of this tutorial, you should be comfortable with the following concepts:

• Object-Oriented Programming (OOP) in Python 3
• Working with JSON data
• Python Type Checking
• Handling HTTP requests

The linked resources will help you better understand the code that you write in this tutorial. However, in this tutorial, you’ll build your app step by step. So even if you’re not familiar with the concepts above, then you’ll be able to follow along.

Step 1: Prepare Your Environment

In this step, you’ll prepare the development environment for your FastAPI app. First, you’ll create the folder structure for your app. Then, you’ll create a virtual environment and install all project dependencies that you need for your project. Finally, you’ll learn how to store environment variables outside of your code and how to load the variables into your app.

Create the Project’s Folder Structure

In this section, you’ll create your project structure. You can name the root folder of your project any way you like. For example, you could name it url_shortener_project/.