Like the others described, one online coding test (the same question as other people said - beware of the limitations in the tool - it's not very helpful for debugging), two onsites: first onsite consisted of 3-4 interviews with technical/behavioral questions, second onsite was CEO, VPs and directors trying to sell the company to the candidate. Both onsites did not pose any obvious red flags; the interviewers all seemed normal, nice, and smart (excluding one higher-level person who did not care about listening to me at all and gave an unprepared tech demo). During the application and interviews, when I mentioned my concern for compensation, the recruiter said that we will work something out that we both feel good about, which was misleading.

Describe a way you would implement a chat system given an API.