Founding Payments Engineer

About the Role

We are seeking a Founding Payments Engineer to own our money layer. You will architect and build systems that move and track user funds with absolute precision, acting as the guardian of financial integrity for our platform.

Key Responsibilities

• Ledger Architecture: Design double-entry, append-only ledgers where balances are derived from immutable entries. Ensure all postings are idempotent to prevent double-counting during retries or duplicate webhooks.
• Reconciliation & Integrity: Implement continuous automated reconciliation against external bank and processor data. Build break-detection mechanisms that alert instantly when discrepancies arise, maintaining the invariant: total funds = user balances + in-flight transactions + fees.
• Security & Compliance: Enforce encryption for all financial data at rest and in transit. Manage secrets via KMS with rotation policies. Implement robust fraud defense including webhook signature verification, replay protection, rate limiting, and anomaly detection.
• Distributed Systems Mastery: Utilize Go or equivalent typed languages to build async processing pipelines using queues and event streams. Handle settlement timing issues, returns/reversals, dead-letter queues, and exactly-once-style processing guarantees (e.g., via sagas).
• Partner Integration & Redemption: Lead technical integration with payment partners for redemptions, ensuring issued amounts are accurately reconciled against funded sources.

Required Skills

• Languages: Proficiency in Go or another strongly-typed backend language; fluent SQL for transactional database design (Postgres).
• Data Integrity: Deep expertise in isolation levels, locking strategies, and ledger schema design to prevent race conditions.
• Rails Experience: Practical knowledge of ACH/bank rails, including handling returns, reversals, and settlement latency.
• Observability: Ability to build comprehensive logging, metrics, and tracing specifically for money flows to detect subtle financial errors early.

Must-Haves

• Demonstrable experience shipping production systems that handle real money (payments, lending, or marketplaces).
• Proven track record of designing double-entry ledgers and managing complex reconciliation workflows.
• A temperament prioritizing correctness over speed, with a rigorous approach to edge cases in financial logic.