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!).
We agree—Zitadel is a strong platform. Our main challenge as an infrastructure product is balancing flexibility with ease of use. While we offer a lot of adaptability for different use cases, getting started can be daunting. We're actively working to make our onboarding process smoother so users can get up and running more quickly. For example we just started working on a lot of improvements on our SDKs as well as a template login app in nextjs that people can fork.
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!