SCIM

SCIM, the "System for Cross-domain Identity Management", is a provisioning protocol. You can use it to automate the provisioning of users across your different apps.

It provides a schema for core identity resources (such as users and groups) and a set of REST operations.

The API is implemented by many Identity Providers (like Okta) and it lets you provision users automatically on apps like GitHub, AWS SSO, and Jira.