demo · v148
Login Flow Walkthrough
A visual play-through of the agentic FedCM exchange. Click "step" to advance one stage at a time and watch the messages move between the three actors: the relying party, the user's agentic browser, and the identity provider.
Backend-backed
The stepper explains the agentic flow. The trace button calls the live showcase FedCM IdP endpoints: config, accounts, client metadata, assertion, and validation.
relying party
example.shop
agentic browser
User agent
identity provider
accounts.idp.example
Browser API probe has not run yet.
No endpoint trace yet.- User agent navigates the agent to
example.shop/checkout. The page renders a<login>element advertising "Sign in with IDP". - The agent decides login is required. It calls
navigator.credentials.get({ identity: {...} })with the relying party's preferred IDP. - Browser asks IDP for the user's available accounts. IDP returns the accounts the user has at this IDP (or "I haven't seen you").
- Browser shows the FedCM dialog. In the agentic flow, the dialog is annotated so the agent can read it programmatically (no DOM scraping).
- User picks an account (or the agent picks one on their behalf, given prior consent). Browser asks IDP for an ID token.
- Browser returns the ID token to
example.shop. The site verifies it and the agent continues the checkout.
what's new vs current FedCM
- IDP-initiated invitations — an IDP can invite a user to log in to a relying party without the RP needing to call the API first.
<login>element — a declarative way to advertise "this is the login button" so the agent doesn't have to look for a button with the right text.- Potentially Approved Sites — for sites the user has visited before, the dialog can be skipped or simplified.
see also
implementation reference
Need the exact API surface, compatibility boundaries, errors, lifecycle, and source links? Read the matching gendn reference ↗