Px uses libcurl and supports all the authentication mechanisms supported by libcurl.

Requires Python ≥ 3.10

Installation

pip install px-proxy
uv tool install px-proxy
pipx install px-proxy

On Windows, Winget and Scoop can also be used:

winget install genotrance.px scoop install px

Prebuilt binaries and offline wheel packages are available on the releases page. See the installation guide for all options including Docker, WinSW, and source installs.

Quick start

# Run with an upstream proxy
px --proxy=proxyserver.com:8080
Run with a PAC file
px --pac=http://example.com/proxy.pac
Run with verbose logging
px --proxy=proxyserver.com:80 --verbose
Save configuration to px.ini
px --proxy=proxyserver.com:8080 --save
Test connectivity
px --test

Configuration

Px can be configured via command-line flags, environment variables (PX_*), dotenv files, or px.ini. See px --help for all options.

Common options:

| Flag | Description | |------|-------------| | --proxy=HOST:PORT | Upstream proxy server(s), comma-separated | | --pac=URL | PAC file URL or local path | | --port=NUM | Listening port (default 3128) | | --gateway | Allow remote clients | | --hostonly | Restrict to local interfaces | | --noproxy=LIST | Hosts/IPs that bypass the upstream proxy | | --auth=TYPE | Force upstream auth type (ANY, NTLM, NEGOTIATE, BASIC, NONE) | | --username=DOMAIN\user | Username for upstream proxy auth | | --log=4 | Log to stdout (verbose mode) |

Full reference: Configuration

Credentials

If SSPI is not available, provide --username in domain\username format. The password is stored in the system keyring:

px --username=domain\username --password

PX_PASSWORD can be used as an alternative when keyring is not available.

See the usage guide for platform-specific keyring setup and client authentication.

Documentation

| | | |---|---| | User guides | | | Installation | pip, wheels, binary, Docker, Winget, Scoop, WinSW, uninstallation | | Usage | Credentials, client auth, examples, dependencies, limitations | | Configuration | All CLI flags, environment variables, INI keys, auth types | | Developer guides | | | Architecture | Runtime model, package layout, data flow, state management | | Build | Build system, pyproject.toml, GitHub Actions, wheels, Nuitka, Docker | | Testing | Test suite layout, running tests, fixtures, coverage | | Reference | | | Changelog | Release history |

Development

Requires uv.

git clone https://github.com/genotrance/px.git
cd px
make install
make test

| Target | Description | |---|---| | make install | Create venv, install dependencies, install pre-commit hooks | | make check | Run linters (ruff) and type checking (mypy) | | make test | Run tests with coverage | | make benchmark | Run concurrency benchmarks | | make test-large-data | Run large data transfer reliability tests | | make docker | Build local Docker images (full and mini) | | make test-kerberos | Build KDC images and run Kerberos integration tests | | make build | Build sdist and wheel | | make clean | Remove build artifacts |

Contributing

Bug reports and pull requests are welcome at .

1. Fork and clone the repository.
2. make install to set up the venv and pre-commit hooks.
3. Create a feature branch, make changes, add tests in tests/.
4. make check && make test — all checks must pass.
5. Open a pull request.

Feedback

Px is definitely a work in progress and any feedback or suggestions are welcome. It is hosted on GitHub with an MIT license so issues, forks and PRs are most appreciated. Join us on the discussion board, Gitter or Matrix to chat about Px.

Credits

Thank you to all contributors for their PRs and all issue submitters.

Px is based on code from all over the internet and acknowledges innumerable sources.