went through the slack new grad SWE process this spring, class of 2025. sharing because the info out there skews toward senior IC and i spent a week trying to piece together what the entry level loop actually looks like.
short answer: it's a real interview but they're not expecting you to have system design mastery.
the rounds i had: online assessment - two leetcode-style questions, 90 minutes. i got one medium and one that felt like a medium/hard. the OA is proctored but the environment is standard. don't overthink the setup, just practice on the actual LC platform so you know the shortcuts. recruiter screen - 20-ish minutes. asked me about projects, why slack, timeline. she was friendly. nothing hard. technical phone screen - 45 min with a senior SWE. one coding question, trees/graphs territory. my interviewer was patient and asked me to think aloud the whole way through. i made an error, caught it, fixed it, and they told me after that catching it myself was noted positively. virtual onsite (3 rounds same day) - two coding rounds + one behavioral. the coding was: one LC medium on strings, one on dynamic programming (honestly i think this was the hardest part). behavioral was with a different engineer and asked about a project i'd worked on, what went wrong, how i handled disagreement with a teammate.
what i wish i'd done: prepped more behavioral before the onsite, i underprepared that part because i was focused on coding. they actually cared. written out my best 3-4 project stories in STAR format ahead of time. i fumbled on "tell me about a time you had a conflict" because i hadn't thought it through. asked about the team during the behavioral round instead of saving questions for the end. didn't matter but it's a thing you can do.
turnaround was 8 days from onsite to offer. they moved fast. good luck to anyone going through it.