Rillet·Backend Engineer·Technical Phone Screen
Apr 2026
Pair-programming interview at Rillet for a backend role where you build an Account Service from scratch in Python using TDD, incrementally adding features while the interviewer watches every keystroke. Pretty intense format if you're not used to writing tests before code.
- Build an Account Service incrementally using TDD in Python, starting from a blank project. Each feature (open account, deposit, withdraw, transfer, balance lookup, overdraft rules) gets a failing test first, then the simplest passing implementation, then a refactor.
“The red-green-refactor rhythm sounds obvious until someone is watching you type and you instinctively want to write the full implementation before the test.”