Thank you for being interested in contributing to HTTPX. There are many ways you can contribute to the project:

Reporting Bugs or Other Issues

Found something that HTTPX should support? Stumbled upon some unexpected behavior?

Feel free to open an issue at the issue tracker. Try to be more descriptive as you can and in case of a bug report, provide as much information as possible like:

  • OS platform
  • Python version
  • Installed dependencies and versions (python -m pip freeze)
  • Code snippet
  • Error traceback


To start developing HTTPX create a fork of the HTTPX repository on GitHub.

Then clone your fork with the following command replacing YOUR-USERNAME with your GitHub username:

$ git clone

You can now install the project and its dependencies using:

$ cd httpx
$ scripts/install

Testing and Linting

We use custom shell scripts to automate testing, linting, and documentation building workflow.

To run the tests, use:

$ scripts/test


The test suite spawns testing servers on ports 8000 and 8001. Make sure these are not in use, so the tests can run properly.

You can run a single test script like this:

$ scripts/test -- tests/

To run the code auto-formatting:

$ scripts/lint

Lastly, to run code checks separately (they are also run as part of scripts/test), run:

$ scripts/check


Documentation pages are located under the docs/ folder.

To run the documentation site locally (useful for previewing changes), use:

$ scripts/docs-serve

Resolving Build / Travis Failures

Once you've submitted your pull request, the test suite will automatically run, and the results will show up in GitHub. If the test suite fails, you'll want to click through to the "Details" link, and try to identify why the test suite failed.

Failing PR commit status

Here are some common ways the test suite can fail:

Check Job Failed

Failing Travis lint job

This job failing means there is either a code formatting issue or type-annotation issue. You can look at the job output to figure out why it's failed or within a shell run:

$ scripts/check

It may be worth it to run $ scripts/lint to attempt auto-formatting the code and if that job succeeds commit the changes.

Docs Job Failed

This job failing means the documentation failed to build. This can happen for a variety of reasons like invalid markdown or missing configuration within mkdocs.yml.

Python 3.X Job Failed

Failing Travis test job

This job failing means the unit tests failed or not all code paths are covered by unit tests.

If tests are failing you will see this message under the coverage report:

=== 1 failed, 435 passed, 1 skipped, 1 xfailed in 11.09s ===

If tests succeed but coverage isn't 100% you will see this message under the coverage report:

FAIL Required test coverage of 100% not reached. Total coverage: 99.00%

Look at the coverage report from codecov for the pull request for help debugging coverage.


This section is targeted at HTTPX maintainers.

Before releasing a new version, create a pull request that includes:

  • An update to the changelog:
    • We follow the format from keepachangelog.
    • Compare master with the tag of the latest release, and list all entries that are of interest to our users:
      • Things that must go in the changelog: added, changed, deprecated or removed features, and bug fixes.
      • Things that should not go in the changelog: changes to documentation, tests or tooling.
      • Try sorting entries in descending order of impact / importance.
      • Keep it concise and to-the-point. 🎯
  • A version bump: see

For an example, see #362.

Once the release PR is merged, run $ scripts/publish to publish the new release to PyPI.