Not open source, but free as in beer: https://curity.io/product/community/ https://curity.io/product/community/ It's a complex server, but if you need to conne

Not open source, but free as in beer: https://curity.io/product/community/ https://curity.io/product/community/ It's a complex server, but if you need to connect to lots of third party systems it may be a good choice as it has support for all sorts of things and its plugins are open-source (e.g. BitBucket plugin: https://github.com/curityio/bitbucket-authenticator https://github.com/curityio/bitbucket-authenticator)