Comprehensive guides on modern authentication methods including PassKeys, WebAuthn, FIDO2, OTP, Magic Links, Social Sign-In, Enterprise SSO, and passwordless solutions. Your complete resource for implementing secure, scalable authentication systems.
The WebAuthn user id must never hold an email address. Here is what the spec forbids, what breaks when you ignore it, and what to store instead.
WebAuthn server registration, beyond the spec: verify the attestation response, store AAGUID and BE/BS, and ship the parts the codelab skips.
Your WebAuthn RP ID is permanent. Get the scope wrong and you invalidate every passkey you have issued. How to pick apex vs subdomain, safely.
Passkey not working in a browser? Here are the exact browser, OS, and password manager combinations that break passkeys in 2026, with a workaround for each.
A passkey AAGUID reference: map the 16-byte authenticator ID to iCloud Keychain, Google Password Manager, 1Password, and more, and use it in support and analytics.
Conditional UI browser support decoded: which Chrome, Safari, and Firefox versions run passkey autofill, which OS pairings break it, and how to detect it.