Senior Backend Engineer, API

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 work on Gamma, the core backend powering Polymarket's markets platform. Gamma processes every market creation, trade, and resolution on the platform: at scale, under load, with no margin for error. You'll ship features with direct product impact, push the boundaries of what the system can handle, and help define how ownership evolves as the platform grows. If you want your work to matter immediately and visibly, this is that role. What You'll Do Architect and implement Go-based services. Design and build services capable of sustaining high request throughput with low latency at scale. Define and enforce engineering standards. Own API versioning strategy, error handling conventions, and service health benchmarks across the backend. Uphold code quality. Drive quality through code reviews, shared conventions, and technical documentation that the broader team can build on. Partner cross-functionally. Collaborate with teams across product and infrastructure to align backend services with broader company goals. Own reliability. Contribute to on-call rotations and drive reliability improvements informed by incident trends and system behavior. What We're Looking For 5+ years of production Go experience: fluent in Go idioms, interfaces, and concurrency patterns Strong API and microservices architecture experience: designing, implementing, and maintaining REST and GraphQL APIs at scale Deep SQL expertise with PostgreSQL or MySQL, plus familiarity with non-relational stores including Redis and ClickHouse Event-driven architecture experience: messaging systems like Redpanda or Kafka, real-time data pipelines, and gRPC service communication Hands-on observability and monitoring experience with Prometheus, Grafana, or OpenTelemetry for tracing, metrics, and alerting (Plus) 1+ years of production Rust experience (Plus) Familiarity with prediction markets, trading platforms, or financial systems (Plus) Experience with blockchain or Web3 systems, particularly EVM-based (Plus) Prior experience in a fast-paced startup environment Benefits Competitive salary & equity Unlimited PTO Full Health, Vision, & Dental coverage 401k match Hardware setup: new MacBook Pro, big display, & accessories