Senior Backend Engineer, Exchange Systems

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. The company is experiencing rapid growth, with $21B traded in 2025, and aims to become a ubiquitous beacon of truth in global media. Polymarket is seeking a Senior Backend Engineer to join its DeFi Trading team. This role involves owning core improvements to exchange systems, working with low-latency APIs, high-throughput data streams, and settlement-aware order state, with a specific focus on evolving the CLOB engine for increased speed, safety, and concurrency at scale. The ideal candidate will clearly understand how on-chain transaction lifecycle, confirmations, reorgs, balances, approvals, and execution outcomes affect off-chain exchange state, tackling deep problems with immediate production visibility. Responsibilities include: owning the CLOB engine's critical path, profiling matching and orderbook hot paths, mapping settlement-sensitive state transitions, and driving latency, throughput, and async engine flow improvements; reducing lock contention, debugging concurrency issues, designing safer queuing and backpressure for orderbooks to handle more markets and order flow with lower tail latency; building for observability and safety with pprof, metrics, logs, and traces, establishing rollback guarantees and narrower critical paths; reasoning about settlement risk and designing systems to correctly handle crossed books, ghost fills, stale orders, cancel inconsistencies, and settlement edge cases; improving the Go runtime by reducing GC pressure, optimizing CPU and memory allocation behavior for high-throughput demands; and debugging production incidents end-to-end, driving follow-through for measurable system improvements.