Senior Backend Engineer, Fintech Payments & LLM

The profile is a highly experienced backend engineer with a strong background in fintech, having served as the second engineer at an a16z-backed company. They owned the entire payment stack for two years, managing ACH, wire, check, and card rails, a double-entry PostgreSQL ledger, and robust webhook pipelines. This platform successfully processed over $150M across 1,800+ customers with zero overdrafts and duplicate payment entries. Key achievements include leading a 10-month migration from Firebase to PostgreSQL without any service interruption. They demonstrated advanced debugging skills by resolving a complex race condition in ACH settlement logic. More recently, they developed a SOC 2 audit agent using LangGraph, significantly optimizing tool calls. The individual is seeking founding engineer or backend roles, open to both remote and on-site positions, and is willing to relocate to the UK, Europe, or the US with sponsorship.