Reloading Swagger on Code Changes with FastAPI

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.7+ based on standard Python type hints. It is built on top of standard Python type hints so it can be fully used in modern IDEs for auto-completion, type checking, linting, and other tools. FastAPI comes with built-in support for Swagger UI, which allows you to automatically generate interactive API documentation.

One of the challenges in developing FastAPI applications is that, by default, Swagger UI is generated only once and does not automatically update when your code changes. This means that if you make changes to your API endpoints, request or response models, you need to manually restart your server to see the updated Swagger UI documentation.

However, to solve this problem, FastAPI provides a reload feature that automatically reloads your server on code changes. By using this feature, you can trigger the regeneration of Swagger UI documentation whenever you make changes to your code.

How to Reload Swagger on Code Changes with FastAPI

First, make sure you have FastAPI installed in your Python environment:

pip install fastapi

Once you have FastAPI installed, you can create a FastAPI application and enable the reload feature using the following code:

from fastapi import FastAPI

app = FastAPI(debug=True)

By setting the debug=True parameter when creating your FastAPI application, the reload feature will be enabled, which will automatically reload your server on code changes.

With the reload feature enabled, you can now make changes to your API endpoints, request or response models, and simply save your files. Your FastAPI server will automatically reload and regenerate the Swagger UI documentation with the updated changes.

Conclusion

Reloading Swagger on code changes with FastAPI is a powerful feature that allows you to easily develop and test your APIs without the hassle of manually restarting your server to see the updated documentation. By enabling the reload feature, you can save time and streamline your development process, making it easier to iterate on your API designs and quickly see the results.