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

These control-plane APIs are used to fully manage the Content Fragments and their associated Models.

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

This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.

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