About Seamless Auth
Seamless Auth is an open source authentication system built to remove passwords, redirects, and hosted identity flows. It is designed to run as part of your infrastructure and integrate directly with your frontend and API.
What passwordless means
Passwordless authentication replaces shared secrets with cryptographic verification. Instead of storing passwords, users authenticate using device bound credentials such as passkeys, WebAuthn, or one time verification codes.
No shared secrets
There are no passwords to reuse, steal, or leak. Authentication relies on cryptographic proof rather than stored secrets.
Server verified identity
Each login is verified by the server using signed challenges that can only be completed by authorized devices.
Reduced user friction
Users authenticate using built in device capabilities rather than remembering credentials or resetting passwords.
How Seamless Auth works
- The user initiates authentication from the application
- The auth server issues a cryptographic challenge
- The user’s device signs the challenge
- The server verifies the signature
- A secure session is established using HTTP only cookies
Once a session is established, all subsequent requests are validated server side. The frontend does not manage tokens or secrets.
Open source by default
Seamless Auth is developed as open source software. You can run it locally, inspect the code, and deploy it into your own infrastructure without vendor lock in.
Managed hosting as an option
For teams that prefer not to operate authentication infrastructure, a managed hosting option is available. The managed service runs the same software with the same security model.
Our mission
Seamless Auth exists to make strong authentication easier to build, easier to understand, and easier to operate without sacrificing control or transparency.