Don't bother wasting your valuable time interviewing with this company.

Slack's interview process consists of a short (very uninformative) phone call and a coding challenge. Despite what the recruiter promises, they provide absolutely no feedback or guidance and do not respond to emails in a timely manner throughout the process. Slack uses the coding challenge as a time buffer for themselves, but it's really a waste of time.

The manager and infra engineer I spoke with over the phone seemed more interested in fixing bugs and "multi-tasking" during the call than taking the time to get to know the candidate. I was really turned off by their unprofessionalism and rude attitude.

After they finally replied to my email, I promptly replied and told them I was not interested in discussing the offer.

Phone call, followed by a take-home coding assignment.