1st round was an introductory call. Was surprised to see the co-founders themselves in it, instead of the usual HR people. Discussions were mostly about previous projects and experiences.
2nd call was a technical one. Had some Dev team members also in it. Got asked a lot of questions about what they use or plan to use.
3rd call was with the Team lead and it was more like a friendly discussion about the work culture and the expectations from both sides.
Last call was a 1-on-1 salary discussion, and they were quick to make sure my demands were met.