The community around FastF1 is slowly building and everyone is welcome to contribute to the project.

Submitting a bug report

If you find a bug in the code or documentation, do not hesitate to open a new issue in the issue section on Github. You are also welcome to post feature requests or pull requests.

If you have more general questions or problems that likely are not caused by a bug in FastF1, you can open a new discussion instead.

If you are reporting a bug, please do your best to include the following:

  • A short, top-level summary of the bug. In most cases, this should be 1-2 sentences.

  • A short, self-contained code snippet to reproduce the bug, ideally allowing a simple copy and paste to reproduce. Please do your best to reduce the code snippet to the minimum required.

  • The actual outcome of the code snippet.

  • The expected outcome of the code snippet.

  • The FastF1 version and Python version that you are using. You can grab the version with the following commands:

    >>> import fastf1
    >>> fastf1.__version__  
    >>> import platform
    >>> platform.python_version()  

We have preloaded the issue creation page with a Markdown template that you can use to organize this information.

Thank you for your help in keeping bug reports complete, targeted and descriptive.

Requesting a new feature

Please post feature requests in the issue section on Github.

Since FastF1 is an open source project with limited resources, you are encouraged to also participate in the implementation as much as you can.

Contributing code

How to contribute

The preferred way to contribute to FastF1 is to fork the main repository on GitHub, then submit a “pull request” (PR).

A brief overview is:

  1. Create an account on GitHub if you do not already have one.

  2. Fork the project repository: click on the ‘Fork’ button near the top of the page. This creates a copy of the code under your account on the GitHub server.

  3. Clone this copy to your local disk:

    git clone<YOUR GITHUB USERNAME>/Fast-F1.git
  4. Enter the directory and install the local version of FastF1. See Setting up FastF1 for development for instructions

  5. Create a branch to hold your changes:

    git checkout -b my-feature origin/master

    and start making changes. Never work in the master branch!

  6. Work on this copy, on your computer, using Git to do the version control. When you’re done editing e.g., fastf1/, do:

    git add fastf1/
    git commit

    to record your changes in Git, then push them to GitHub with:

    git push -u origin my-feature

Finally, go to the web page of your fork of the FastF1 repo, and click ‘Pull request’ to send your changes to the maintainer for review.

Contributing pull requests

It is recommended to check that your contribution complies with the following rules before submitting a pull request:

  • If your pull request addresses an issue, please use the title to describe the issue and mention the issue number in the pull request description to ensure that a link is created to the original issue.

  • All public methods should have informative docstrings with sample usage when appropriate. Use the google docstring standard.

  • Formatting should follow the recommendations of PEP8, as enforced by ruff. The maximum line length for all changed lines is 79 characters. You can check code style compliance from the command line with

    python -m pip install ruff
    ruff check .

    or your editor may provide integration with it. The above command will not flag lines that are too long!

    Ruff will also be run before each commit if you have the pre-commit hooks installed (see Installing additional dependencies for development).

  • Changes (both new features and bugfixes) should have good test coverage. See Testing for more details.

  • Import the following modules using the standard scipy conventions:

    import numpy as np
    import pandas as pd
    import matplotlib as mpl
    import matplotlib.pyplot as plt
  • If your change is a major new feature, add an entry to the Changelog section by editing docs/changelog.rst


The current state of the FastF1 code base is not compliant with all of those guidelines, but we expect that enforcing those constraints on all new contributions will move the overall code base quality in the right direction.

Contributing documentation

You as an end-user of FastF1 can make a valuable contribution because you more clearly see the potential for improvement than a core developer. For example, you can:

  • Fix a typo

  • Clarify a docstring

  • Write or update an example plot

The documentation source files live in the same GitHub repository as the code. Contributions are proposed and accepted through the pull request process. For details see How to contribute.

If you have trouble getting started, you may instead open an issue describing the intended improvement.

Coding guidelines

Supported versions of Python and dependencies

This project supports:

  • All minor versions of Python released 42 months prior to the project, and at minimum the two latest minor versions.

  • All minor versions of Numpy, Pandas and Matplotlib released in the 24 months prior to the project, and at minimum the last three minor versions.

  • For other dependencies: As a guideline, this project will try to support all minor versions initially released in the 12 months prior to our planned release date or the oldest that supports our minimum Python. We will only bump these dependencies as we need new features or the old versions are no longer compatible with other minimum version requirements of this project.

These guidelines are based on NEP 29 .

API changes

API consistency and stability are of great value. Therefore, API changes (e.g. signature changes, behavior changes, removals) will only be conducted if the added benefit is worth the user effort for adapting.

API changes in FastF1 have to be performed following the deprecation process below, except in very rare circumstances as deemed necessary by the developers. This ensures that users are notified before the change will take effect and thus prevents unexpected breaking of code.

Note that FastF1 often needs to be adapted to changes in external APIs which may come without prior warning. To be able to efficiently keep up with these external changes, it can be necessary to make changes to FastF1 on shorter notice than described below. In general, breaking changes and deprecations should be avoided if possible and users should be given prior warnings and as much time as possible to adapt.


  • Deprecations are targeted at the next point release (e.g. 3.x)

  • Deprecated API is generally removed two point-releases after introduction of the deprecation. Longer deprecations can be imposed by core developers on a case-by-case basis to give more time for the transition

  • The old API must remain fully functional during the deprecation period

  • If alternatives to the deprecated API exist, they should be available during the deprecation period


  1. Announce the deprecation in the changelog docs/changelog.rst (reference your pull request as well)

  2. If possible, issue a DeprecationWarning when the deprecated API is used, using the python warnings module.


  1. Announce the deprecation in the changelog docs/changelog.rst (reference your pull request as well) For the content, you can usually copy the deprecation notice and adapt it slightly.

  2. Change the code functionality and remove any related deprecation warnings.

Adding new API

Every new function, parameter and attribute that is not explicitly marked as private (i.e., starts with an underscore) becomes part of FastF1’s public API. As discussed above, changing the existing API is cumbersome. Therefore, take particular care when adding new API:

  • Mark helper functions and internal attributes as private by prefixing them with an underscore.

  • Carefully think about good names for your functions and variables.

  • Try to adopt patterns and naming conventions from existing parts of the FastF1 API.

  • Consider making as many arguments keyword-only as possible. See also API Evolution the Right Way – Add Parameters Compatibly.

New modules and files: installation

  • If you have added new files or directories, or reorganized existing ones, make sure the new files are included in the match patterns in in packages in setup.cfg.

Using logging for debug messages

FastF1 uses a logging system that is based on the standard Python logging library to write verbose warnings, information, and debug messages. Please use it! In all those places you write print calls to do your debugging, try using logger.debug instead!

FastF1 creates one main logger and then uses child loggers for each module.

To include logging in your module, at the top of the module, you need to add from fastf1.logger import get_logger. Then calls in your code like:

# set up the logger once (!)
logger = get_logger(__name__)

# code'Here is some information')
logger.debug('Here is some more detailed information')
# more code

will log to a logger named fastf1.yourmodulename.

Which logging level to use?

There are five levels at which you can emit messages.

  • logger.critical and logger.error are really only there for errors that will end the use of the library but not kill the interpreter.

  • logger.warning is used to warn the user, for example, if an operation has failed gracefully, if some action is likely to have unintended side-effects or similar.

  • is for information that the user may want to know if the program behaves oddly. For instance, if a driver did not participate in a session, some data cannot be loaded for this specific driver. But FastF1 can still be used normally with data of all other drivers in this session.

  • logger.debug is the least likely to be displayed, and hence can be the most verbose. Information that is usually only required for development and debugging of FastF1 should be logged here.

By default, in FastF1, logging displays all log messages at levels higher than logging.INFO to sys.stderr.

Allowing optional functions to fail gracefully

FastF1 processes lots of data that may change unexpectedly, contain unknown values or that is not always available. Of course, the best way to deal with this is to write code that is as robust as possible. But of course, it is not always possible to foresee what unexpected data your code might need to deal with. In some cases, FastF1 cannot work without some specific data being processed correctly. But in other cases, FastF1 can still be used with limited functionality if we prevent it from crashing when such an error is encountered. Examples for such cases are:

  • loading optional data: weather data, telemetry, …

  • doing additional (cross) validation of data

  • applying corrections to improve the accuracy of data

If such a task fails, we want FastF1 to show a warning to the user. But especially if such an error is encountered during data loading, it should not crash FastF1 and make the whole session unavailable to the user. Loading incomplete data is always preferred over loading no data at all.

To deal with this, FastF1 provides a special function decorator called fastf1.logger.soft_exceptions() that can be used as follows:

from fastf1.logger import soft_exceptions

@soft_exceptions(descr_name="optional data processing",
                 msg="Failed to do some optional data processing",
def _optional_data_loading():

The basic functionality of this decorator is to wrap a one big try: … except Exception: … clause around the function call. But additionally, if the function call fails, the msg is shown to the user, using the logging level WARNING. The traceback is logged with the logging level DEBUG and prefaced with the line “Traceback for failure in {descr_name}”. You need to pass the logger for the current module as a third argument to the decorator.

This catch-all exception handling makes development more difficult, because for example a debugger won’t be able to stop on an unhandled exception. Therefore, it is possible to easily disable the exception handling for all functions that are decorated in this way. This is described in detail here: Logging - fastf1.logger.