Senior Backend Engineer, Product 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 volume ($21B traded in 2025) and in adoption as an alternative news source. Our ambition is to become a ubiquitous beacon of truth in global media, powered by fast, reliable, and deeply technical market infrastructure. ABOUT THE ROLE Polymarket is looking for a backend/product engineer to own the core domain APIs and data models that power our consumer-facing product. You’ll work at the intersection of backend infrastructure and product, shipping the primitives that frontend, mobile, and product teams build on top of — with high ownership and a strong bias toward execution. WHAT YOU’LL DO - Design core domain APIs: Build and evolve the APIs and data models that underpin Polymarket’s consumer product at scale. - Build real-time infrastructure: Develop gRPC/Connect services and real-time streaming systems (e.g., WebSocket-to-gRPC-stream migrations) alongside event and notification infrastructure. - Ship end-user features: Partner directly with frontend, mobile, and product teams to deliver features like personalization, search, and live data feeds. - Unify fragmented systems: Consolidate fragmented services and APIs into cleaner, reusable primitives that speed up future feature development. - Balance debt and delivery: Pragmatically balance technical-debt cleanup with shipping new product surface area under tight deadlines. - Collaborate cross-functionally: Work closely with engineers across product, infra, and data to ensure tight integration with the broader platform. WHAT WE’RE LOOKING FOR - Backend/product engineering experience designing and evolving domain APIs and data models for a consumer-facing product at scale. - Hands-on experience with gRPC/Connect and real-time streaming (e.g., WebSocket-to-gRPC-stream migrations) and event/notification infrastructure. - Track record partnering directly with frontend, mobile, and product teams to ship end-user features. - Experience unifying fragmented services and APIs into cleaner, reusable primitives. - Pragmatic judgment for balancing technical-debt cleanup with shipping new product surface area under P0 deadlines. - (Plus) Experience at a high-growth consumer product company or marketplace. - (Plus) Experience deploying systems in cloud environments (AWS/GCP) and using containers. BENEFITS - Competitive salary & equity - Unlimited PTO - Full Health, Vision, & Dental coverage - 401k match - Hardware setup — new MacBook Pro, big display, & accessories