Clerk is an authentication and authorization service platform.
It can be included easily into web apps and offers a solid free-tier of 10000 monthly active users.
On the downsides, it might be slow and scales very expensively, once you need more than 10000 monthly active users.
Development vs. production mode
Alternatives
- Self-hosting Supertokens might be a good idea
- Keycloak is also fully selfhostable
- https://logto.io/pricing offers an even better free trial