Technical proficiency
Probe depth on consensus and replication: Raft or Paxos internals, leader election, quorum reads, exactly-once semantics, and hands-on work with Kafka, etcd, Cassandra or Spanner.
Evidence to listen for
- Command of the languages, frameworks, and data tools the role actually uses
- Understands correctness, performance, and failure modes, not just syntax
- Has opinions on testing and can justify them
- Reads and reasons about code they did not write
Five-point scoring guide
Cannot work independently; fundamentals are missing.
Weak fundamentals; output needs heavy review.
Competent for the role; needs guidance on complex or unfamiliar work.
Strong practitioner; handles hard problems with little guidance.
Explains quorum trade-offs, clock skew and partition behaviour precisely, citing config details from systems they personally operated at scale.