Why it matters
SSO moves authentication to the customer’s identity provider. It still leaves your app responsible for tenant routing, provisioning, permissions and recovery when an identity configuration fails.
A successful SSO handshake only proves identity. Your application still needs to map that identity to the right customer, choose an access level and handle a broken connection without locking everyone out.
Decisions to make
- Choose SAML, OIDC or both based on the customers you actually serve.
- Define how a domain maps to an organization without assuming every email domain is exclusive.
- Keep a recovery path for customer administrators and your own support team.
- Choose whether customers can require SSO for everyone or allow exceptions.
- Define how an IdP user maps to an existing account when email or subject changes.
Build checklist
- Test first login, returning login, account linking and offboarding.
- Validate issuer, audience, signatures and redirect targets.
- Document certificate rotation and the steps to recover a broken connection.
- Test expired certificates, changed issuer values and invalid redirects.
- Make the connection status and last successful login visible to administrators.
Common mistakes
- Equating successful authentication with permission to join a particular organization.
- Using email domain matching as the only tenant routing rule.
- Treating an IdP account deletion as immediate local session revocation without implementing it.
Tools & references
4 starting points to compare or study. Check fit, maintenance, terms and current capabilities before choosing one.
