Single Sign-On (SSO)
One company login opens every app the company uses, so nobody keeps a separate password per tool.
See it
What it is
Single Sign-On means one authentication at a central identity provider (Okta, Entra ID, Google Workspace) unlocks every app that trusts it. Your app stops storing passwords for those users entirely: it redirects to the IdP, gets back a signed assertion saying who the person is, and creates a local session from that.
You reach for SSO when you start selling to companies. It is the item that appears in every security questionnaire, usually alongside SCIM for automatic provisioning and deprovisioning. Two protocols carry it: SAML, old, XML, still what large enterprises ask for by name, and OIDC, modern, JSON, easier to implement. Expect to support both if your buyers are big.
Gotchas that bite: SSO is not the same as social login, even though both are 'log in with someone else'. SSO is org-scoped, so you need to route a user to the right IdP by email domain before you know who they are. And single sign-on does not imply single sign-out: killing the IdP session rarely kills the sessions in every downstream app, so plan global sign-out deliberately.
Ask AI for it
Add enterprise SSO to this app. Support both SAML 2.0 and OIDC, configured per organization, with the IdP chosen by the email domain the user types on a domain-first login screen. On successful assertion, do just-in-time provisioning: create the user if they are new, map IdP group claims to app roles, and start a normal app session. Add an admin screen where a customer pastes their metadata URL or certificate, and support global sign-out that revokes every session for that user.