b2KIT

Passkey Compatibility Tester

Test your browser and device support for passkeys (WebAuthn). Check platform authenticator and cross-platform capabilities.

Tested tool guide Tested browser tools Checked August 16, 2026

What Passkey Compatibility Tester does and how it behaves

This tool runs the browser's own WebAuthn feature-detection calls and reports what comes back: whether window.PublicKeyCredential exists, whether isUserVerifyingPlatformAuthenticatorAvailable() resolves true (a built-in authenticator like Touch ID, Windows Hello, or a fingerprint sensor is present), and whether isConditionalMediationAvailable() is supported (passkey autofill in login forms). It only reads what your current browser and OS expose - it never creates or verifies a real credential. People are often surprised a green result here doesn't guarantee a production login works, since that also depends on server-side relying-party origin and configuration.

How the result is produced

1

Feature detection, not credential creation

The tool checks for window.PublicKeyCredential and, if present, awaits PublicKeyCredential.isUserVerifyingPlatformAuthenticatorAvailable() and isConditionalMediationAvailable(). These are standard WebAuthn methods that report browser and OS capability without prompting for a fingerprint, face scan, or PIN, and without any network request or server involvement.

2

Platform vs cross-platform authenticators

It distinguishes a platform authenticator (built into the device, e.g. Touch ID or Windows Hello) from cross-platform support (a security key over USB/NFC/BLE, or a phone acting as a hybrid authenticator via QR code). Cross-platform support is inferred from general WebAuthn API presence, since no browser API directly enumerates attached external authenticators.

Good uses

  • Confirming a laptop or phone can use Touch ID, Windows Hello, or a fingerprint sensor as a passkey authenticator before rolling out passwordless login
  • Checking whether a specific browser version supports passkey autofill (conditional UI) so a login form knows whether to offer it
  • Diagnosing why a passkey prompt fails to appear on one device, by isolating browser/OS support from server-side relying-party configuration

Limits and checks

  • A passing result confirms browser and OS capability only - it says nothing about whether your relying-party server, RP ID, or allowed origins are configured correctly
  • isUserVerifyingPlatformAuthenticatorAvailable() can return true when the hardware exists even if no fingerprint or face is actually enrolled yet, so an authenticator can still fail or prompt for enrollment on first real use
  • Private/incognito windows, enterprise device policies, and remote desktop or VM sessions can report different or reduced capability than a normal window on the same physical machine

Common questions

If this page says my browser is fully supported, will my site's passkey login definitely work?

No. This only checks client-side WebAuthn capability. Your site's login will still fail if the relying-party ID doesn't match the origin, if the server rejects the attestation, or if the credential was registered under a different origin. Test the actual registration and login flow separately.

Why does it say no platform authenticator is available on my Mac even though I use Touch ID elsewhere?

This can happen in a browser or profile where Touch ID hasn't been granted permission, inside a VM without biometric hardware passthrough, in some private browsing modes, or on an older browser version that hasn't yet implemented isUserVerifyingPlatformAuthenticatorAvailable().

References and verification

The behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

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