Senior Backend Engineer — Payments Platform
senior · version v1-Mft0Fe
58fd32b5-4151-4e1b-aa1c-ab2538f8b850
Competencies
weights sum to 1.00| Name | ID | Weight | Definition |
|---|---|---|---|
| Financial Systems Design | financial_systems_design | 0.30 | Design and implement bulletproof payment state machines with guaranteed idempotency, atomicity, and recoverability. Every state transition must be reversible and handle edge cases involving real money movement (double-entry accounting, settlement, reconciliation). |
| Distributed Systems Reliability | distributed_systems_reliability | 0.25 | Build systems that handle ordering guarantees, consensus failures, and retry semantics correctly. Demonstrate deep understanding of exactly-once delivery challenges and implement patterns that prevent state corruption across service boundaries and network failures. |
| Postgres Schema Design for Scale | postgres_schema_design | 0.20 | Design normalized schemas for high-throughput transactional workloads with strong consistency requirements. Optimize for payment processing at millions-per-day scale while maintaining query performance and avoiding deadlocks. |
| Production Ownership & Incident Culture | production_ownership | 0.15 | Own services end-to-end including on-call responsibility. Drive postmortem-to-fix cycles that prevent recurrence, and take ownership of critical payment path outages or reconciliation issues. |
| FastAPI & Event-Driven Architecture | fastapi_kafka_systems | 0.10 | Build services in FastAPI with event-driven patterns using Kafka or similar log-based messaging. Design service boundaries that decouple payment state changes from side effects. |
Scoring Weights
Adjust how much each competency contributes to the final score. Changes apply to all future evaluations for this job spec.
financial_systems_design
30%0.30
distributed_systems_reliability
25%0.25
postgres_schema_design
20%0.20
production_ownership
15%0.15
fastapi_kafka_systems
10%0.10
Total weight: 1.00 ✓ balanced
Interview questions
AI-generated from the JD · auto-published · edit anytime3 currently · candidate sees this many
Behavioral round (Round 02)
Voice Q&A · pre-generated from the JD · edit anytime4 prompts · Cal walks through each in order during Round 02
Live performance
Aggregated from candidates who took this job spec.
Interviews
1
0 completed
Avg score
—
out of 100
Completion
0%
0 of 1
Avg score per competency
Financial Systems Designweight 0.30—n=0
Distributed Systems Reliabilityweight 0.25—n=0
Must-haves
- required5+ years shipping production backend systems in Python
- requiredStrong SQL expertise with experience designing schemas for transactional workloads on Postgres
- requiredDemonstrated understanding of distributed systems fundamentals (consensus, ordering, idempotency, exactly-once semantics)
- requiredTrack record of owning production incidents, writing postmortems, and preventing repeat failures