What are the best Authentication & Authorization APIs? (2026)

Easy to implement, adaptable authentication and authorization platform

To access files in user’s DigiLocker account from your application, you must first obtain user’s authorization.

Drop-in React components for authentication and authorization

Passkey-first authentication

For more information on how to use these APIs, including how to create an API key required for authentication, see [Alma REST APIs](https://developers.exlibrisgroup.com/alma/apis).

Implement OTP flow quickly

Authentication for modern applications. Integrates in minutes and free up to 7,500 MAU

The Labs64 <a href='https://netlicensing.io/wiki/restful-api' target='_blank'>NetLicensing RESTful API</a> gives you access to NetLicensing’s core features.<br/><br/><strong>Authentication</strong>...

User management and authentication

Secure and modern passwordless authentication platform

Simplify login and improve user experience by integrating passwordless authentication in your app

User infrastructure for modern applications

This is a sample server Petstore server. You can find out more about Swagger at [http://swagger.io](http://swagger.io) or on [irc.freenode.net, #swagger](http://swagger.io/irc/). For this...

APIs for authorization and access control