completed the AIG virtual onsite last month. here's the actual breakdown because the vague prep guides don't tell you what the flow feels like.
mine was 4 rounds, back to back with 10-minute breaks. fully virtual, Zoom. they sent a schedule the day before.
round 1: system design (60 min) see other posts on this. mine was about designing a real-time risk assessment system for underwriting. they wanted to see how I'd balance latency with accuracy, and how I'd handle model updates without downtime. went well.
round 2: coding (45 min) live coding, not leetcode. shared editor, interviewer watched and asked questions. the problem was medium level, more of a real-world programming task than a puzzle. I had to parse a nested config format and validate it against a schema. not a tree problem per se but tree-shaped. I think they care more about whether you write clean, readable code than whether you hit optimal complexity.
round 3: behavioral (50 min) engineering manager. substantial. see other posts about AIG behavioral questions. the EM was genuinely curious, not reading from a script. good conversation.
round 4: architecture and experience (45 min) this one is underrepresented in writeups. it was with a senior engineer, not a manager. they had read my resume in detail. they asked me to go deep on a past project: what would I change, what tradeoffs were wrong in retrospect, how would I approach it differently with what I know now. it's less of an interview and more of a senior engineering conversation. I liked it a lot.
debrief timing: recruiter reached out 5 business days later. that felt long but apparently normal for AIG. don't panic at the silence.
overall feel: professional, respectful, no trick questions. the interviewers had clearly talked to each other before the loop. felt like a company that had thought about how to evaluate engineers, not just going through motions.