Applied online through the careers website and was emailed a few weeks later to set up an initial chat with a recruiter. It seemed the the recruiter was fairly new at Slack and couldn't answer questions regarding Slack's engineering teams as well as products/features that I used. It was going well until the recruiter asked about the percentage of time I spent on the backend vs. frontend. Expecting a predominately backend distribution the recruiter quickly told me that he would not be moving forward with me as I told him I was a full stack developer and spent my time equally between both domains. I would say that this is a poor representation of what I thought Slack was, why even setup an initial chat and screen me as a candidate if you intuition is to hire someone based on their answer of how much time they have spent on a technology? Additionally asking a percentage of how much one works on the backend or frontend does not determine their aptitude of that knowledge. I may spend 50% frontend/50% backend but I definitely am adept at both principles.

My experience is similar to many others' experiences here. I believe they post jobs and do some interviews to show their presence in the market but do not have much to offer.