Clerk offers a full-stack user management platform that handles authentication and user management for you. It includes features like multifactor authentication, advanced security, session management and social sign-on. It's highly customizable and integrates with popular frameworks and tools, and offers a variety of pricing tiers depending on your needs.
Another good option is Auth0, which offers secure access and fine-grained control over user permissions. With features like Universal Login, Single Sign On and Passwordless authentication, Auth0 is designed to scale up from small startups to large enterprises. It also offers a free plan so you can try it out before moving to a paid plan.
If you want to go passwordless, MojoAuth offers a secure and convenient login option for web and mobile apps. The platform eliminates the vulnerabilities of passwords, offering better security and a better user experience. It's designed to work with code and no-code integration, so developers can easily manage user identities.