If your plan is to connect other services then I'd suggest using LDAP for central authentication.
It can easily be connected to any API without much "glue". And most common open source services already support it as auth backend.
It's also easier to audit than any custom service you might concoct on your own because auditors already have experience with it through Active Directory.
It can easily be connected to any API without much "glue". And most common open source services already support it as auth backend.
It's also easier to audit than any custom service you might concoct on your own because auditors already have experience with it through Active Directory.