Best Practices for Securing Partner APIs with FusionAuth

wesley

We use FusionAuth for user authentication on our website and plan to expose certain API endpoints to external partners. Our idea is to have partners authenticate via FusionAuth and then use the access token (JWT) to call our secured APIs.

Is this the recommended way to secure partner APIs with FusionAuth? Should we separate partner users into a different tenant or application for better isolation? And if partners need server-to-server access, is the client credentials grant the right approach?

wesley

Yes—using FusionAuth access tokens to secure partner-facing APIs is a solid approach. The key is ensuring the tokens contain the right claims to enforce proper authorization for your endpoints.

Separating partners into a different tenant or application can improve security and simplify management. Different tenants fully isolate users and tokens, but would require duplicating application configs. Alternatively, you could keep partners in the same tenant and distinguish them via roles, claims, or separate applications.

If partners are accessing APIs server-to-server, the client credentials grant (Entities in FusionAuth) is the correct choice. Be sure to carefully scope each partner’s access to avoid over-permissioning.