* [Tryton](http://www.tryton.org/) - Free open source business solution. ([Demo](http://demo.tryton.org/), [Source Code](https://hg.tryton.org/)) `GPLv3``Python/Javascript`
* [Tryton](http://www.tryton.org/) - Free open source business solution. ([Demo](http://demo.tryton.org/), [Source Code](https://hg.tryton.org/)) `GPLv3``Python`
## Federated Identity/Authentication
* [FreeRADIUS](http://freeradius.org/) - High performance and highly configurable multi-protocol policy/authentication server, supporting RADIUS, DHCPv4 and VMPS. ([Source Code](https://github.com/FreeRADIUS/freeradius-server)) `GPLv2``C`
* [daloRADIUS](http://www.daloradius.com) - Open-source web management platform for FreeRADIUS-based deployments. ([Source Code](https://github.com/lirantal/daloradius)) `GPLv2``PHP`
* [FreeIPA](https://www.freeipa.org/) - an integrated Identity and Authentication solution for Linux/UNIX networked environments. A FreeIPA server provides centralized authentication, authorization and account information by storing data about user, groups, hosts. `Multiple``C`
* [IndieAuth](https://indieauth.com) - Sign in with your domain name (using the [rel-me-auth](http://microformats.org/wiki/relmeauth) protocol). `Apache``Ruby`
* [Libravatar](https://www.libravatar.org/) - Libravatar is a service which delivers your avatar (profile picture) to other websites. ([Demo](https://www.libravatar.org/account/new/), [Source Code](https://github.com/libravatar/libravatar)) `AGPLv3``Python`
* [OpenCA OCSPD](https://pki.openca.org/projects/ocspd/) - An [OCSP](https://en.wikipedia.org/wiki/Online_Certificate_Status_Protocol) Responder.
* [OpenID/OpenID Connect](http://openid.net/developers/libraries/) - A Simple Identity layer on top of OAuth 2.0.
* [OSIAM](https://www.osiam.org) - Open Source Identity and Access Management implementing OAuth 2.0 and SCIMv2. ([Source Code](https://github.com/osiam/osiam)) `MIT``Java`
See https://github.com/n1trux/awesome-sysadmin#identity-management