Ramp Software Engineer Interview Experience — URL Maze BFS Tech Screen with Flaky 503s and a Silent Interviewer

Just finished my Ramp tech screen today, so here's the writeup.

Process: one hour, one question, 5 minutes of Q&A at the end.

Question: URL Maze (a classic that keeps showing up in past interview reports)

You're given a start URL. Calling it returns JSON where the key is next_stops and the value is a list of paths. You append each path to the host and keep visiting, until some URL returns {"message": "congrats"}, which means you've found the exit.

The approach is classic BFS. The traps aren't in the algorithm:

1. The interviewer gave zero clarification: no hints at all, I had to figure everything out by trying inputs and looking at the output. I asked about edge cases (503s, JSON parse failures) and got ignored.
2. The biggest trap: the responses are non-deterministic. The same URL might return 503 this time, and a retry might work fine. At first I just skipped anything that returned 503, and ended up missing the exit. Wasted a long time debugging that.
3. Optimization: per-endpoint max retry + visited dedup.

How it felt: stumbled through it. Debugging that 503 retry trap took way too long, and I didn't have time left for the follow-up. I thought the interviewer would be more collaborative, but I was figuring it out on my own the whole time.