Senior Backend Engineer, Exchange Infrastructure

ABOUT POLYMARKET 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. 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 and we need your help adding fuel to the fire. ABOUT THE ROLE Polymarket is looking for a Senior Backend Engineer to join our DeFi Trading team and own core improvements to our exchange systems. You'll work across low-latency APIs, high-throughput data streams, and settlement-aware order state and with a specific focus on evolving our CLOB engine to be faster, safer, and more concurrent as the platform scales. This role requires someone who can reason clearly about how on-chain transaction lifecycle, confirmations, reorgs, balances, approvals, and execution outcomes affect off-chain exchange state. The problems are deep, the stakes are real, and the work will be immediately visible in production. WHAT YOU'LL DO - Own the CLOB engine's critical path. Profile matching and orderbook hot paths, map settlement-sensitive state transitions, and drive improvements to latency, throughput, and async engine flow backed by benchmarks and production-grade evidence. - Reduce lock contention without breaking correctness. Debug concurrency issues, design safer queueing and backpressure for orderbooks, and improve the system's ability to handle materially more markets and order flow with lower tail latency. - Build for observability and safety. Instrument improvements with pprof, metrics, logs, and traces. Establish rollback guarantees and narrower critical paths that make production incidents easier to detect, diagnose, and resolve. - Reason about settlement risk. Understand how on-chain transaction effects ripple into off-chain exchange state, and design systems that handle crossed books, ghost fills, stale orders, cancel inconsistencies, and settlement edge cases correctly. - Improve the runtime. Reduce GC pressure, optimize CPU and memory allocation behavior, and push Go runtime performance to meet the demands of a high-throughput exchange at scale. - Debug production incidents. Own latency, correctness, and settlement-state incidents end-to-end, and drive follow-through that leaves the system measurably better each time. WHAT WE'RE LOOKING FOR - Senior+ backend or systems engineer with production ownership of an exchange system — perp DEX, crypto exchange, or any high-throughput trading backend with on-chain settlement - Hands-on experience with matching engines, order routing, or market data infrastructure where tail latency, correctness, and rollback safety were real constraints - Deep Go expertise — you've tuned GC pressure, optimized hot paths, and understand the runtime internals that matter in a high-throughput exchange context - Strong concurrency skills with a real track record: lock contention, race conditions, async correctness, and backpressure under load - Profiling experience you've actually used in production — pprof, flamegraphs, and metrics to find and fix latency problems, not just describe them - EVM/blockchain transaction lifecycle experience: you understand how confirmations, reorgs, and on-chain state ripple into off-chain exchange correctness - Strong CS fundamentals: algorithms, data structures, and systems-level thinking - (Plus) Rust experience - (Plus) Redis, PostgreSQL, gRPC, Protobuf - (Plus) Kubernetes and AWS production operations BENEFITS - Competitive salary & equity - Unlimited PTO - Full Health, Vision, & Dental coverage - 401k match - Hardware setup: new MacBook Pro, big display, & accessories