Senior Software Engineer, Ledger

San Francisco, California

Development - Full Stack

Permanent

Our client, early-stage Fintech company in San Francisco, are hiring a Senior Software Engineer to join the team remotely. The successful candidate will build and evolve the double-entry ledger that serves as the platform’s financial system of record, while playing a key role in shaping the next generation of the platform, including a major ledger rebuild and the expansion of payment infrastructure.

Responsibilities

Own and evolve the double-entry ledger, covering transactions, balances, holds, reversals, payment states, point-in-time balances and comprehensive audit trails.
Design and build highly reliable money-movement infrastructure across ACH, instant payments, wires, cards and emerging settlement rails.
Develop scalable payout and settlement systems, supporting instant payouts, batch processing and high-volume marketplace transactions.
Build automated reconciliation systems that detect and resolve discrepancies across internal ledgers, banking partners and payment processors.
Design and scale the infrastructure underpinning lending products, including disbursements, repayments, partial payments, reversals and complex loan lifecycles.
Build resilient multi-provider payment architecture, incorporating webhooks, idempotency, retries, state machines and robust failure handling.
Develop controls for high-value financial transactions, including fraud prevention, disputes, chargebacks, limits, holds and settlement management.
Ensure complex financial activity is translated into a clear and intuitive customer experience, including balances, transaction histories, funding sources and settlement activity.
Make pragmatic architectural decisions that balance delivery speed with financial accuracy, reliability, scalability and long-term maintainability.
Provide senior technical leadership through architecture, code reviews, documentation and mentorship, raising engineering standards across the team.

Skillset

Minimum of 5 years of professional software engineering experience, with a strong focus on backend, payments, fintech or financial systems.
Strong proficiency in Python, PostgreSQL, AWS, SQL and relational data modelling.
Hands-on experience building and operating real-world money movement systems, including ACH, instant payments, wires, cards or comparable payment rails.
Experience designing, building, migrating or owning a double-entry ledger in a production environment.
Strong understanding of webhooks, idempotency, race conditions, state machines, eventual consistency and reconciliation.
Experience building highly reliable systems for high-value financial transactions, where accuracy, resilience and traceability are critical.
Strong knowledge of transactional database architecture, particularly for high-volume, concurrent and financially sensitive workloads.
Experience within payments, fintech, lending, marketplaces or other complex financial transaction environments.
Strong ownership and product mindset, with the ability to balance speed, financial correctness, customer experience and long-term architecture.
Experience with React and TypeScript would be a plus.