(I'm a cofounder of Tesseral)

We're huge fans of Better Auth -- it's a really great offering. They might have their own take on how we differ, but here's my best attempt at a quick comparison.

We take pretty different approaches to roughly the same family of problems.

Better Auth is focused on being a great library for TypeScript. If you write Typescript and want to build your own auth, they're a great bet.

We're more of an API-first service that's agnostic to the language or framework that you use. We have a pretty opinionated product that is meant to handle auth for you -- it's not really an auth library per se.