demo · v133

WebAuthn capability matrix — tailor the sign-in UI to the device

Before designing a passkey UI, sites had to try a flow and see if it errored. PublicKeyCredential.getClientCapabilities() returns a flat map of supported features — conditional UI, related origin requests, payment confirmation, hybrid transport — in one call, so the UI can hide buttons the device can't honour.

capabilitysupportedUI suggestion

what to do with each capability

A few of the capabilities the spec defines — the Chrome 133 implementation returns these and a few more vendor-specific keys:

keyused to enable
conditionalCreatesilently upgrade a password sign-in to a passkey on the next visit
conditionalGetautofill-style passkey picker inside the username field
hybridTransportshow "sign in with another device" option (QR / cloud assistance)
relatedOriginsshare passkeys across owned domains (paypal.com ↔ paypal.me)
passkeyPlatformAuthenticatorshow OS-level "use a passkey on this device" CTA
userVerifyingPlatformAuthenticatorrequire biometric/PIN on creation
signalAllAcceptedCredentialstell the OS to prune deleted passkeys

see also