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Development - Contributing

First, you might want to see the basic ways to help and get help.


Once you’ve cloned the repository, here are some guidelines to set up your environment:

Set up the development evironment

After cloning the repository, you can use poetry to create a virtual environment:

$ make develop

Behind the scenes, this checks that you have python3 and poetry installed, then creates a virtual environment and installs the dependencies. At the end, it will print out the path to the executable in case you want to add it to your IDE.

Activate the environment

Once the virtual environment is created, you can activate it with:

$ poetry shell

To check if this worked, try running:

$ which python


If the output of this command shows the python binary in a path containing fastapi-utils somewhere in the name (as above), then it worked! 🎉


Every time you install a new package with pip under that environment, activate the environment again.

This makes sure that if you use a terminal program installed by that package (like mypy), you use the one from your local environment and not any other that could be installed globally.

Static Code Checks

This project makes use of black, autoflake8, and isort for formatting, flake8 for linting, and mypy for static type checking.

To auto-format your code, just run:

$ make format

It will also auto-sort all your imports, and attempt to remove any unused imports.

You can run flake8 with:

$ make lint

and you can run mypy with:

$ make mypy

There are a number of other useful makefile recipes; you can see basic documentation of these by calling plain make:

$ make


The documentation uses MkDocs.

All the documentation is in Markdown format in the directory ./docs.

Many of the sections in the User Guide have blocks of code.

In fact, those blocks of code are not written inside the Markdown, they are Python files in the ./docs/src/ directory.

And those Python files are included/injected in the documentation when generating the site.

Docs for tests

Most of the tests actually run against the example source files in the documentation.

This helps making sure that:

  • The documentation is up to date.
  • The documentation examples can be run as is.
  • Most of the features are covered by the documentation, ensured by test coverage.

During local development, there is a script that builds the site and checks for any changes, live-reloading:

$ bash scripts/

It will serve the documentation on

That way, you can edit the documentation/source files and see the changes live.


You can run all tests via:

$ make test

You can also generate a coverage report with:

make testcov

On MacOS, if the tests all pass, the coverage report will be opened directly in a browser; on other operating systems a link will be printed to the local HTML containing the coverage report.

Tests in your editor

If you want to use the integrated tests in your editor add ./docs/src to your PYTHONPATH variable.

For example, in VS Code you can create a file .env with: