Senior Backend Engineer, Payments

Polymarket•New York, NY

About The Position

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. 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.

Requirements

Senior-level backend engineering experience with payments, fintech, or financial-data integrations (processors like Stripe, banking rails, card networks).
Proven track record leading migrations from legacy/monolith systems to reliable distributed services (Go, gRPC, DynamoDB/MySQL) without production disruption.
Experience partnering with Product, Compliance, and Design to ship regulated or high-stakes financial features (KYC/EDD, fraud, reconciliation).
Comfortable owning production on-call for money-movement systems where correctness and auditability are critical.
Track record of mentoring, onboarding, and driving team process (backlog grooming, tech-debt reduction).

Nice To Haves

Experience in crypto, prediction markets, or other high-growth regulated fintech environments.
Experience deploying systems in cloud environments (AWS/GCP) and using containers.

Responsibilities

Build payments infrastructure: 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.
Integrate with financial rails: Build and maintain integrations with payment processors, banking rails, and card networks to support deposits, withdrawals, and settlement.
Ship regulated features: Partner cross-functionally with Product, Compliance, and Design to deliver high-stakes financial features such as KYC/EDD, fraud checks, and reconciliation.
Own correctness and auditability: Take ownership of production on-call for money-movement systems where correctness, reliability, and auditability are non-negotiable.
Drive team process: Mentor engineers, onboard new hires, and lead backlog grooming and tech-debt reduction efforts.
Collaborate cross-functionally: Work closely with engineers across the platform to keep payments systems tightly integrated with the broader exchange.