otp.com
Send and verify one-time codes through a shared API
Authentication SDKs
Add sign-in, sessions, and authorization to an application.
MonoCloud
Add branded authentication and manage application user sessions
FusionAuth
Deploy API-driven authentication and identity management
SuperTokens
Add customizable sign-in and session management to applications
Stytch
Authentication and authorization APIs for users and agents
WorkOS
APIs for enterprise authentication, directories, and audit logs
Descope
Design login and identity workflows with a visual editor
Clerk
Add sign-in and user management to web applications
Auth0
Authentication and authorization for applications