(I am a cofounder of Tesseral)
Honestly, I'm not intimately familiar with Zitadel's solution. At a quick glance, it seems quite powerful! But it does seem like our product is more opinionated -- and is more narrowly focused on serving B2B applications.
I suspect that if you have the appetite and experience to build something unusual or otherwise complex, Zitadel will be a great fit. Perhaps they are like Keycloak in this respect. On the other hand, we try very hard to steer developers into a 'pit of success' by abstracting away a lot of details that most people don't need to worry about.
But I'll admit that comparison may be inaccurate; I probably will have to look in more detail. (The comparison will certainly seem wrong months / years into the future as our companies evolve!).
You are building an auth and you didn't even bother doing a in depth look at what Zitadel does ???? This doesn't communicate any serious commitment or product depth. Zitadel already does B2B very well and it is not only mature but very flexible to use across much of the enterprise space.
Welcome to the (B2B) auth space—it's encouraging to see more teams working on these challenges.
From our experience at Zitadel, we’ve found that mid-market and enterprise customers often also look for industry standards like SAML and OpenID Connect to integrate their services, so we’ve made those a core part of our offering—including providing fully compliant SAML and OpenID Connect endpoints. It looks like Tesseral is taking a more focused approach with SDK and API integrations for web apps, which makes a lot of sense for many teams starting out.
We also believe that, over time, the distinction between B2C and B2B use cases will blur, and both will be consolidated into a potent, unified identity infrastructure platform. That’s the direction we’re building toward with Zitadel.
Wishing you all the best as Tesseral grows. If you ever want to swap stories about auth, don't hesitate to reach out!