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.
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
NoPass.me - Open-source identity verification
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Authenteq - User-owned and controlled blockchain-based online ID
Better Uptime - We call you when your website goes down