We know the Stack Auth team well, and we really respect what they're up to! We have a really high opinion of them. I'd be curious how they'd assess the comparison.

First, of course you can often use either of our two products in many cases. We do compete!

Second, I think we focus on subtly different customers. There are cases where they're a better fit and cases where I'd assess us to be a better fit. For example, Stack Auth is pretty closely aligned to the Next.js ecosystem. They're really quite strong at serving Next.js. They also have a billing and payments product that's likely interesting to companies with a heavy self-service motion. On the other hand, Tesseral serves only B2B software, and we're not as focused on Next.js (SDK currently in the works). If, for instance, you have a Go backend and sell large enterprise-y deals, we're probably a better fit.

But this will probably evolve over time. I'd expect this comparison to be outdated within a few months.

Overall, I expect our companies will drift in slightly different directions over time. We're both very early stage companies that have focused on pretty foundational features so far.