Senior iOS Engineer

Job description

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 iOS Engineer to help build our iOS product as we invest seriously in mobile. This is a high-ownership role for someone who understands what it takes to build a great trading or wagering experience on mobile — the performance requirements, the real-time data challenges, the UI patterns that make fast-moving information feel intuitive rather than overwhelming. You'll work closely with product, design, and engineering leadership to deliver a high-quality iOS experience and help raise the bar across the mobile codebase. The right person has been in this world before: they know what a great trading or sportsbook app feels like from the inside, and they want to build something better. WHAT YOU'LL DO - Take end-to-end ownership of Polymarket's iOS experience, from technical architecture and performance to product quality and release discipline - Make and own architectural decisions for the iOS platform, ensuring the codebase is built to scale and maintained with rigor as the product grows - Design and implement experiences that handle live market data, fast-moving prices, and real-time order state in a way that feels fast and reliable to users - Lead code reviews, establish strong iOS engineering standards, and help grow the capability of the broader mobile team - Work closely with product, design, and backend teams to align on priorities, define APIs and data contracts, and ship high-quality experiences end-to-end - Help shape how Polymarket thinks about mobile as a platform, including architecture decisions that set up the team for scale WHAT WE'RE LOOKING FOR - Significant iOS engineering experience, with a track record of shipping and owning high-quality iOS applications in production - Deep experience building trading, financial, or sportsbook applications — you understand the product domain and the technical demands that come with it - Strong knowledge of Swift and the iOS SDK, with solid instincts around performance, memory management, and real-time data handling - Experience building apps that consume live data feeds and display fast-moving information reliably and smoothly - A high bar for product quality — you care about how things feel, not just whether they work - Comfortable operating with broad ownership in a fast-moving environment - Strong cross-functional communication skills — you work well with product, design, and backend engineers - (Plus) Familiarity with WebSockets, streaming APIs, or other real-time data infrastructure - (Plus) Experience leading or mentoring iOS engineers - (Plus) Background in a high-growth startup environment BENEFITS - Competitive salary & equity - Unlimited PTO - Full Health, Vision, & Dental coverage - 401k match - Hardware setup: new MacBook Pro, big display, & accessories