Affirm Staff Engineer: recruiter and HM screens, a recursive revenue HackerRank and a payment processing design with idempotency keys

Started with a recruiter call, then HM screening, a virtual onsite with 2 technical rounds (coding and system design) and a hiring manager behavioral interview. My recruiter was quite helpful and gave me a breakdown of the full process before I started. Also she was very quick in getting back to me after each round. Overall a very standard and positive interview experience.

The screening rounds were all as you would expect. Outlining the role, what the team do, if I had any questions etc. Just make sure you know your resume inside out and have plenty of STAR structured answers prepared. Use the behavioral playbook and just match the questions to your past experiences and you'll pass it. Everyone I spoke to was so lovely so the conversations all flowed nicely and felt very amicable.

The coding round was a DSA question using HackerRank and the question was to do with computing total revenue of a shop across all of its branches using recursion.

The system design round was to design a payment processing system. Had to handle payments, ledger consistency, idempotency. The interviewer went deep on how to use idempotency keys to prevent double charges during timeouts and retries, and when I finished they followed up with handling loan servicing as an add on.