Polymarket is the world's largest prediction market platform, enabling 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. We're growing fast — both in terms of volume ($21B traded in 2025) and adoption as an alternative news source. Our ambition is to become a ubiquitous beacon of truth in global media. Polymarket is looking for a world-class backend engineer with deep blockchain knowledge to join our Onchain Execution team. This team owns the systems that sit between Polymarket's product and the chain — the relayers, transaction pipelines, RPC infrastructure, and settlement logic that make every trade possible. You'll be working on technically demanding problems at the intersection of distributed systems, blockchain protocols, and high-throughput backend engineering. The ideal candidate brings both fundamentals (clean code, solid databases, well-designed APIs) and fluency in how EVM networks actually work under the hood. If you've built or maintained relayer systems, worked on scalable RPC infrastructure, or contributed to core blockchain node software, this role is a strong match. You will build and maintain onchain execution infrastructure, designing and operating relayer systems, transaction pipelines, and settlement logic. You will architect high-performance backend systems, building reliable, scalable APIs and services that handle high transaction volumes and real-time data with low latency. You will own RPC and chain connectivity, implementing and scaling endpoints and integrations for EVM networks. Responsibilities also include optimizing performance and reliability across onchain systems, enhancing security and fault tolerance using best practices for secure, highly available distributed systems in adversarial onchain environments, contributing to code quality through active participation in code reviews, and staying close to the frontier by tracking developments across EVM ecosystems and blockchain infrastructure to bring relevant innovations back to Polymarket's stack.