SuperTokens

Open-source authentication you self-host, with the session logic readable rather than opaque.

Auth you can step through in a debugger.

What it is sold for

Running authentication without a third party in the path.

The address redirects to https://supertokens.com/, which is worth knowing before you follow it.

The rest of security and secrets, alphabetically. Sharing a category is a filing decision, not a relationship.

Aserto

Fine-grained authorization as a service, so permission checks stop being scattered if-statements.
Auth0

Hosted identity: login, federation, multi-factor and the standards work nobody wants to implement twice.
AWS Cognito

Amazon's managed identity for consumer applications, priced and scaled for very large user pools.
Bearer

Static analysis for security and privacy risk, focused on where sensitive data flows. Acquired by Cycode.
Bearer CLI

The open-source scanner behind Bearer. Finds and ranks security and privacy risk in source, and still runs on its own.
BoxyHQ Enterprise SSO

Open-source SAML and OIDC single sign-on, so enterprise login is not a rewrite. The address now serves Ory.
Checkmarx

Enterprise application security, combining several scan types and consolidating findings into one risk view.
Clerk

Authentication with the interface components included, built for React and Next.js first.

ImranTools[SuperTokens]