The well-known stun gun company Axon, phone screen. I applied for Senior Engineer I. HR told me the phone screen would already need to happen in San Diego, and only after that would they decide which direction to move me in. The interviewer was a senior engineer, with a newly joined staff engineer shadowing.
The question was pretty much the same as other write-ups on this forum — it was about uploading recorded camera footage. The main things being tested were how to handle large blobs, malicious content detection, and chain of custody. The first two were roughly similar to designing Dropbox; for the last one, just asking ChatGPT would basically get you the solution.
Here's how I answered in the interview.
Large Blob
Me: Chunk the blob client-side and upload in batches. You can use S3's multipart upload to reassemble the chunks.
Interviewer: What if you can't trust the cloud provider's multipart upload?
Me: Then add a cron job that, when the upload completes, downloads the object chunks, reassembles them, and re-uploads.
Malicious Content Detection
Me: Use two buckets to separate things — one publicly available, one a quarantine bucket. A blob that just finished uploading stays in the quarantine bucket first, waiting for a security scan. Once that's done, it gets moved to the public bucket so it can later serve as evidence in court.
Chain of Custody
For this one I referenced a similar write-up from this forum, and also asked ChatGPT for some ideas. To sum it up: every operation needs a checksum attached, and each checksum is derived by hashing the previous operation's checksum together with some random number. By this point the interviewer already seemed pretty satisfied.
A couple days later the recruiter emailed to schedule the next round. Next week I'm going onsite to perform!
By the way, their second round (onsite) has 5 total: coding x2 + system design x2 + BQ. I looked it up on LinkedIn and one of the rounds is apparently with the Senior Director & Chief of Staff. Is their interview lineup really that stacked? They're bringing out senior directors and C-suite people too?
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