Senior Backend Engineer, Payments at Polymarket

<h1>About Polymarket</h1><p style="min-height:1.5em">Polymarket is the world's largest prediction market platform. We enable individuals to express views on real-world events by trading on outcomes across politics, economics, sports, culture, and current affairs. Built as a peer-to-peer marketplace with no centralized “house,” Polymarket aggregates diverse opinions into transparent, market-based probabilities that reflect collective expectations about the future.</p><p style="min-height:1.5em">We’re growing fast: both in volume ($21B traded in 2025) and in adoption as an alternative news source. Our ambition is to become a ubiquitous beacon of truth in global media, powered by fast, reliable, and deeply technical market infrastructure.</p><p style="min-height:1.5em"></p><h1>About the role</h1><p style="min-height:1.5em">Polymarket is looking for a senior backend engineer to build and scale the payments infrastructure that powers deposits, withdrawals, and money movement across the platform.</p><p style="min-height:1.5em">This role sits at the intersection of engineering and regulated financial operations, and requires the judgment to move fast without compromising correctness or auditability. You’ll be a high-ownership individual contributor working closely with Product, Compliance, and Design.</p><p style="min-height:1.5em"></p><h1>What you’ll do</h1><ul style="min-height:1.5em"><li><p style="min-height:1.5em"><strong>Build payments infrastructure: </strong>Design and lead migrations from legacy or monolithic systems to reliable, distributed payments services (Go, gRPC, DynamoDB/MySQL) with no disruption to production money movement.</p></li><li><p style="min-height:1.5em"><strong>Integrate with financial rails: </strong>Build and maintain integrations with payment processors, banking rails, and card networks to support deposits, withdrawals, and settlement.</p></li><li><p style="min-height:1.5em"><strong>Ship regulated features: </strong>Partner cross-functionally with Product, Compliance, and Design to deliver high-stakes financial features such as KYC/EDD, fraud checks, and reconciliation.</p></li><li><p style="min-height:1.5em"><strong>Own correctness and auditability: </strong>Take ownership of production on-call for money-movement systems where correctness, reliability, and auditability are non-negotiable.</p></li><li><p style="min-height:1.5em"><strong>Drive team process: </strong>Mentor engineers, onboard new hires, and lead backlog grooming and tech-debt reduction efforts.</p></li><li><p style="min-height:1.5em"><strong>Collaborate cross-functionally: </strong>Work closely with engineers across the platform to keep payments systems tightly integrated with the broader exchange.</p></li></ul><p style="min-height:1.5em"></p><h1>What we’re looking for</h1><ul style="min-height:1.5em"><li><p style="min-height:1.5em">Senior-level backend engineering experience with payments, fintech, or financial-data integrations (processors like Stripe, ban