Auth0 - Auth0 is a program for people to get authentication and authorization services for their own business use.
UserTesting.com - Usability testing has never been easier. Get videos of real people speaking their thoughts as they use websites, mobile apps, prototypes and more!
Keycloak - Open Source Identity and Access Management for modern Applications and Services.
Userbrain - Easy, fast, and affordable user testing for websites and prototypes.
Amazon Cognito - Amazon Cognito lets you add user sign-up, sign-in, and access control to your web and mobile apps quickly and easily. It scales to millions of users and supports sign-in with social identity providers and enterprise identity providers via SAML 2.0.
userinput.io - Get on-demand feedback for your app, website or idea. Learn how to improve by hearing real opinions.