Passkeys & autofill

Two browser features that, set up once, make signing in and paying for things across the web dramatically faster: passkeys (which replace passwords) and payment-card autofill (which fills card details into checkout forms).

What is a passkey?

A passkey is a credential stored in your phone, computer, or password manager that proves you're you, using your fingerprint, face, or device PIN — no password to remember, no password to phish. When a site supports passkeys, signing in is one biometric tap.

Passkeys are based on a published standard (FIDO2 / WebAuthn) supported by Apple, Google, Microsoft, Mozilla, 1Password, Bitwarden, and others. They sync across your devices if you use iCloud Keychain, Google Password Manager, or a third-party manager.

Create a passkey on a site that supports them

Manifold Chess and other Manifold services that support passkeys will offer to create one during sign-in or in your account settings. The exact label varies — "Set up passkey," "Enable biometric sign-in," "Add security key." The flow is essentially the same:

1. Sign in to the service as you normally would (with your email and whatever sign-in method you currently use).
2. Go to your account or security settings.
3. Find the option labelled Passkey, WebAuthn, or Biometric sign-in and tap it.
4. Your phone or browser shows a prompt: "Create a passkey for [site]?" Tap Continue.
5. Authenticate with Face ID, Touch ID, fingerprint, or your device PIN.
6. Done. Next time you sign in to that site, the passkey option will be offered automatically.

Sign in with a passkey

1. Visit the sign-in page.
2. The site shows a Sign in with passkey option, or your browser proactively suggests it.
3. Tap it, authenticate with biometric or device PIN.
4. You're in. No password.

Where passkeys are stored

On iPhone / Mac: in iCloud Keychain (syncs to all your Apple devices via iCloud). On Android: in Google Password Manager (syncs to all your Android devices via your Google account). On Windows: in Windows Hello. You can also use a third-party password manager (1Password, Bitwarden) that supports passkeys, which gives you a manager that works across all operating systems.

Browser autofill for payment cards

Even without Apple Pay or Google Wallet, your browser can fill card details into checkout forms for you. The browser stores the card locally (and optionally syncs across your devices), encrypted, and asks you for confirmation each time it's used.

Chrome (desktop or Android)

1. Open Settings → Autofill and passwords → Payment methods.
2. Tap Add.
3. Enter card number, expiry, cardholder name, and nickname.
4. Save.
5. Next time you reach a checkout that asks for card details, Chrome will offer to fill them with one tap.

Safari (iPhone, iPad, Mac)

1. iPhone / iPad: Settings → Safari → AutoFill → Saved Credit Cards → Add Credit Card.
2. Mac: open Safari, then Safari menu → Settings → AutoFill → Credit cards → Edit → Add.
3. Enter card details and save. Cards sync via iCloud Keychain to your other Apple devices.

Firefox

1. Menu → Settings → Privacy & Security → Forms and Autofill → Saved payment methods → Add.
2. Enter card details and save.
3. Cards sync across Firefox Sync if you're signed in to a Firefox account.

Autofill vs. Apple Pay / Google Wallet — which is better?

Apple Pay and Google Wallet are strictly better when both your device and the merchant support them: faster (biometric, no fields to fill), more private (real card number isn't shared), and a single confirmation step. Autofill is the fallback when the merchant doesn't offer Apple Pay or Google Wallet — for example, an older checkout form that only takes a raw card number.

Common issues

"Create a passkey" never appears

Either the site doesn't support passkeys yet, or your browser is older than the WebAuthn standard. Passkeys are supported by Safari 16+, Chrome 108+, Firefox 122+, and Edge 108+ on desktop and mobile.

The browser keeps asking me to confirm autofilled cards

That's by design — autofill never silently submits payment info; you always confirm. If you want to skip the confirmation, set up Apple Pay or Google Wallet instead.

I want to use a security key (YubiKey) instead of a phone

YubiKeys and similar hardware keys are also WebAuthn devices and work the same way. When a site asks "Create a passkey," tap the option for "Security key" or "Use another device" and follow the YubiKey prompts.