I did several rounds of interviews, and all of them went well. The recruiters communication was basically non-existent. I was then ignored and gaslighted by the recruiter/mattermost for weeks without any communication. When they gave a response to me 3 weeks overdue, they informed me they were still interested, and they told me they were still discussing out seniority and budget. Yet, while they say this me, they were still advertising the role on Glassdoor and LinkedIn & were clearly waiting for different candidates. The recruiter failed to give me a final update when they said they would, and a week later, I finally received the news they selected another candidate. It took 3 months from applying to be denied and I was only half way done with the application process. Mattermost seems like a company that has very technical people but is mismanaged. Best of luck to you.

A couple round of interviews followed by a presentation of a demo environment with specific use cases configured. They were very open and transparent, and moved quickly in the process, with a follow-up.