Senior Backend Engineer, Onchain

Polymarket•New York, NY

18d•Remote

About The Position

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.

Requirements

5+ years of experience in backend development
Strong fundamentals: clean, well-tested code; solid database design (PostgreSQL or equivalent); well-structured APIs
Solid understanding of how EVM networks work: transaction lifecycle, gas mechanics, mempool dynamics, smart contract interactions
Experience with systems-level languages: Golang is strongly preferred; Rust or C++ also valued
Familiarity with blockchain infrastructure: RPC nodes, event indexing, relayer architectures, or similar
Excellent problem-solving skills and the ability to work through ambiguous, high-stakes technical challenges

Nice To Haves

Direct experience building or operating a relayer system
Experience with Ethereum rollup technologies (Arbitrum Nova, Optimism, etc.)
Experience with BFT consensus engines, libp2p, or core node software
Open source contributor in the blockchain ecosystem
Active on ethresear.ch or similar protocol research forums

Responsibilities

Build and maintain onchain execution infrastructure. Design and operate the relayer systems, transaction pipelines, and settlement logic that power Polymarket's markets end-to-end.
Architect high-performance backend systems. Build reliable, scalable APIs and services that handle high transaction volumes and real-time data with low latency.
Own RPC and chain connectivity. Implement and scale the endpoints and integrations that keep Polymarket reliably connected to EVM networks.
Optimize performance and reliability. Push the limits of throughput and efficiency across our onchain systems, ensuring seamless operation as volume grows.
Enhance security and fault tolerance. Apply best practices for secure, highly available distributed systems — especially in adversarial onchain environments.
Contribute to code quality. Participate actively in code reviews and help maintain a high engineering bar across the team.
Stay close to the frontier. Track developments across EVM ecosystems and blockchain infrastructure, and bring relevant innovations back to Polymarket's stack.