Senior Software Engineer, Predictions (Mobile)

Gemini•New York, NY

7h•Hybrid

About The Position

As a Senior Mobile Engineer on the Predictions team, you'll own the mobile experience for Gemini's CFTC-regulated prediction markets exchange. You'll build and ship trading interfaces for event contracts — from order entry and position management to real-time market data — within Gemini's React Native app. You'll work closely with product, design, backend, and compliance to bring new contract types (binary, range, combo) to market on mobile and drive activation and retention for a fast-growing product line. This role is required to be in person twice a week at our New York City, NY office.

Requirements

6+ years of software engineering experience, including 4+ years building production mobile applications with React Native.
Strong proficiency in TypeScript.
Deep understanding of React Native internals — bridging, native modules, performance profiling, and debugging.
Experience building real-time, data-intensive UIs (trading, dashboards, live feeds).
Strong UX/UI sensibility with a track record of contributing to design and product decisions, not just implementing specs.
Expertise in unit and integration testing for mobile.
Comfort working in a regulated environment where changes require rigor and auditability.

Nice To Haves

Experience with financial or trading applications (orderbooks, charting, position management).
Familiarity with Expo, EAS, and OTA update strategies.
Experience with native module authoring (Swift/Kotlin) or SwiftUI/Jetpack Compose embedding via Expo Modules API.
Exposure to gRPC, WebSockets, or similar real-time transport protocols.
Experience with performance analysis tooling (Flipper, React DevTools profiler, native instruments).
Prior work at a fintech, exchange, or other regulated product environment.

Responsibilities

Build and maintain the Predictions mobile trading experience end-to-end: market browsing, order placement, portfolio views, and settlement flows.
Architect performant, real-time UI for streaming market data (orderbook, price charts, position P&L) using modern React Native patterns (TurboModules, JSI, native navigator integration).
Collaborate with backend engineers on gRPC and WebSocket integrations that power live trading surfaces.
Create reusable, well-tested UI components shared across Predictions and the broader Gemini mobile app.
Partner with product and design to shape mobile-specific UX for new contract categories (weather, economics, crypto, sports) and features like combo contracts and range contracts.
Scope and implement solutions independently, making informed architecture decisions and tradeoffs around native vs. JS boundaries.
Establish and improve mobile development processes — testing strategy, release quality gates, OTA vs. native release decisions.
Conduct thorough code reviews and mentor other engineers on React Native best practices.
Use analytics and experimentation data to inform product and engineering decisions around activation funnels, onboarding, and trading engagement.