We currently use the BSL license, created by MariaDB and used by companies like Sentry. We do think Osso is open source by common understanding and view the BSL as a fair model that places no restrictions on good actors - the license is intended to protect us from copycats profiting off our work, while allowing anyone that needs to integrate SAML into an app they’re building free reign. You’re free to use Osso as a widget, but you can’t use it to start a widget factory.
"Source available" seems like a fair compromise, thanks for the suggestion.
FWIW, We're big fans of Sentry's explanation of the BSL license - https://sentry.io/_/open-source/