Coinbase · Primly Community

went through the full Coinbase loop last month, here's what I saw

backend_bekah · 4 replies

just finished a senior backend eng loop at Coinbase. sharing notes while they're fresh.

recruiter screen: standard 30 min. they asked about distributed systems experience and whether I had any crypto context. I have fintech background, which helped. no real gotchas.

phone screen: one LC medium (graph traversal, nothing exotic), and then about 15 minutes of 'walk me through a high-scale API you've built.' the interviewer was clearly reading signal on whether I could discuss trade-offs, not just recite a design.

onsite (4 rounds, all virtual): coding 1: two mediums back to back, 45 min. one DP, one string manipulation. tight on time. coding 2: one harder problem but they gave hints, felt collaborative system design: design a real-time transaction notification system. they pushed hard on consistency guarantees and failure modes. this is where crypto context actually matters because they want you to reason about settlement windows. behavioral: 3 questions, all ownership and conflict. one was 'tell me about a time you disagreed with a technical decision and had to act on it anyway.' they're looking for how you hold the tension, not for you to say you won.

still waiting on the offer call but the loop itself felt fair. timeline was 3.5 weeks total.

4 replies

sre_sol

the transaction notification system design is a classic Coinbase prompt, I've seen it mentioned twice in this thread and once on blind. the consistency vs. latency framing is the crux. did they ask you about exactly-once delivery or was it more of a 'what happens if you drop a message' thing?

backend_bekah

both, honestly. started with 'what happens if you drop a message' and then moved to exactly-once after I brought up idempotency keys. it felt like they were following my lead on the depth. if you don't bring it up they probably don't push it as hard.

market_realist

3.5 weeks is faster than what I heard from a friend who went through in Q1. he waited 5 weeks and then got a no-hire after the debrief. not trying to dampen your optimism, just, the calibration committee thing can add time unpredictably.

numbers_only

did they tell you the level upfront or was it floated post-loop? I've heard Coinbase sometimes downgrades level after the fact.