Passwordless authentication lets users prove who they are without remembering a secret string. Instead of a password, the system verifies something the user has or controls, like an email inbox, a phone, a security key, or a device bound credential.
A typical flow starts when the user enters an identifier such as an email or username. The app offers methods like a magic link sent to email, a one time code to an authenticator app, or a prompt to use a built in device credential. With passkeys and security keys, the browser and device use WebAuthn to create or use a key pair and sign a one time challenge.
The server verifies the proof. For magic links, it checks the signed link. For one time codes, it checks the code against a short lived record. For passkeys and security keys, it verifies the cryptographic signature and origin. No password is stored or transmitted.
On success, the system starts a session and returns a cookie or a token. Many products issue tokens that work with OAuth or OpenID Connect, or support enterprise federation with SAML.
Developers integrate through hosted pages, client SDKs, and backend APIs. Vault Vision, MojoAuth, Magic, and Stytch provide building blocks for web and mobile apps. Hardware devices like OnlyKey add a physical factor that works with standards based flows and passkeys.
Admins manage policies such as allowed methods, session lifetimes, step up prompts, and risk rules. Logs, webhooks, and dashboards help teams monitor sign ins and troubleshoot.
