It took around 2 weeks in total. 1. Phone screen with the recruiter, 2. A list of questions including culture and tech to be finished at home. 3. A homework project 4. Batch interview. 1st round tech interview with 3 lead engineer, 2nd round with another 2 lead engineer. 3rd round with all 3 co-founders. I spent quite a lot of time on the interview: 3 hours to finish the questions list which including a design questions in it, but they never asked or discussed it during the interview. And the whole weekends on finish the project they sent me. I cleared all the questions during the interview, but rejected because they suspect that there's a 3rd util function used in my project is copied from somewhere in the github. The function is even not required of the project, in other words, the project can be ran perfectly without this function. I felt insulted when they told me the reason of rejection. The chat with co-founders all pleased and you can feel the passion and ambition from them even though they are young guys. But I think the applicant for the backend engineer should seriously consider about it if you got the offer from them.