The radcli library is a library for writing RADIUS Clients. The library's approach is to allow writing RADIUS-aware application in less than 50 lines of C code. It was based originally on freeradius-client and radiusclient-ng and is source compatible with them.

For the development of the openconnect VPN server, I needed a simple library to allow using radius for authentication and accounting without having to understand the internals of radius. Such library was the freeradius-client library, but was undocumented, had too much legacy code centered around radlogin, a tool which is of no significance today, was IPv4-only and had no releases for several years, and zero tests.

This library addresses these shortcomings, adds a test suite and test driven development, adds package management via pkg-config, adds support for TCP, TLS and DTLS, provides documentation of the API, and will include any new features for the task. It is provided as a shared library in case it is useful to other projects as well, and is also made source compatible with radiusclient-ng and freeradius-client.

Documentation and examples are available at: https://radcli.github.io/radcli/

Run autogen.sh to generate the configure script and makefiles.

Required dependencies (Fedora/RHEL pkg):

dnf install -y autoconf libtool automake nettle-devel gnutls-devel gettext-devel libabigail doxygen doxy2man

For adding new features or extending functionality in addition to the code, please also submit a test program which verifies the correctness of operation. See tests/ and .github/workflows for the existing test suite.

AI tool use is assumed and does not require disclosure. What matters is human accountability: every line you submit is your responsibility, regardless of how it was generated. Reviewers will hold you accountable as the author.

If you use AI assistance:

• Follow the guidance in AGENTS.md for all AI-assisted work.
• External contributors should load the radcli-contributor persona (contrib/ai/personas/radcli-contributor.md) before starting.
• Maintainers doing AI-assisted review or development should load the radcli-core-dev persona (contrib/ai/personas/radcli-core-dev.md).

Review calibration: Reviewers may ask how a contribution was developed if it raises quality questions. Be prepared to explain your approach. Submissions that show signs of unchecked generation — hallucinated API calls, missing tests, style inconsistencies — may be returned with a request for additional work rather than an inline review.

Not acceptable: Submitting code you cannot explain or defend. Own your patch.

Please use the issue tracker at: https://github.com/radcli/radcli/issues

The web site https://radcli.github.io/radcli is the primary web-site for radcli and is auto-generated via the 'make web' rule.