v139 · Security · Web Authentication
Web Authentication Immediate UI mode
A new mediation: "immediate" option for navigator.credentials.get() — shows the browser sign-in UI only if a passkey or password is already known for the site, and rejects instantly with NotAllowedError if there is none.
concepts
-
Immediate vs Conditional UI
Side-by-side comparison of
mediation: "immediate"versusmediation: "conditional"versusmediation: "required". Trigger each and observe how the browser responds when no credentials exist. -
Credential Availability Gate
Demonstrates how to use
"immediate"as a gate: try it first; if it rejects, fall through to a traditional sign-in form. Zero prompts for users with no credentials, instant for users who do. -
Three Mediation Modes
One row for each of
conditional,silent, and the newimmediate— with the snippet, a one-click probe, the actual API result, and a matrix that explains UI / gesture / null / reject behaviour. -
Passkey Manager
Register a passkey, then test all four mediation modes — immediate, conditional, required, and a register flow — against the real
navigator.credentialsAPI. Registered credentials appear in a list with remove buttons. ProbesPublicKeyCredential.isConditionalMediationAvailable()on load with a support bar.
why it shipped
The Credential Management API offers mediation: "conditional" (fill autocomplete suggestions silently) and mediation: "required" (always show the picker). But sites needed a middle mode: "show the picker only if you have something to offer." Without it, every page had to choose between always annoying users with a picker, or never showing one at all. mediation: "immediate" fills this gap: it resolves if the browser has a matching passkey or password, and rejects with NotAllowedError otherwise — letting sites display a sign-in form only for users who have no credentials, while offering a frictionless one-tap sign-in for everyone else.