Onyx is building the consumer trading platform for the speculation economy—bringing prediction markets, sports, crypto, and real-world events into one seamless experience.
Following our Series A led by Payward, we’re growing the engineering team behind our real-time, consumer-first trading platform. We’re looking for a Mobile Engineer with strong production experience in React Native, Expo, and TypeScript to build and scale the Onyx mobile experience across iOS and Android.
This is a high-impact opportunity to own mobile features from concept through release and help shape the future of our mobile platform.
What You’ll Do
- Build and scale high-quality mobile applications using React Native, Expo, and TypeScript
- Develop polished, performant user experiences across iOS and Android
- Own features from technical design through development, testing, deployment, and monitoring
- Manage builds, releases, and over-the-air updates using Expo Application Services (EAS)
- Own submissions and releases through the Apple App Store and Google Play Store
- Navigate app review requirements, certificates, provisioning profiles, signing, versioning, and release approvals
- Integrate the mobile application with backend APIs and AWS-based services
- Build real-time experiences powered by live data and streaming updates
- Optimize application performance, responsiveness, reliability, and scalability
- Create reusable components and contribute to scalable mobile architecture
- Partner with Product, Design, Backend Engineering, and Infrastructure to deliver new features
- Debug production issues and improve the customer experience
- Contribute to code reviews, testing, CI/CD workflows, and engineering best practices
What We’re Looking For
- 2+ years of professional mobile engineering experience
- Strong production experience with React Native, Expo, and TypeScript
- Expo experience is required and non-negotiable
- Hands-on experience shipping and maintaining consumer applications through both the Apple App Store and Google Play Store
- Strong knowledge of the end-to-end submission and release process, including app signing, provisioning, certificates, review requirements, versioning, and release management
- Experience with EAS Build, EAS Submit, and Expo Updates
- Strong understanding of mobile architecture, state management, testing, debugging, and performance optimization
- Experience integrating mobile applications with REST APIs and cloud-based services; AWS experience is preferred
- Strong product intuition and attention to detail, with a focus on polished consumer experiences
- Comfortable owning mobile features and releases end-to-end in a fast-moving startup environment
- Experience with animations, WebSockets, real-time data, payments, sports, gaming, fintech, trading, or other interactive consumer products is a plus
- Native iOS experience with Swift and/or Android experience with Kotlin is a plus
Logistics
- Location: NoHo, New York City
- Schedule: Hybrid
- Experience: 2+ years
- Work Authorization: Candidates must already be authorized to work in the United States. Onyx cannot provide current or future visa sponsorship for this role.