Senior Fullstack Engineer, Frontend

Alt is building the financial infrastructure for the modern collector powering payments, lending, pricing, and liquidity for alternative assets. Our flagship mobile app (4.9★ on iOS, 4.6 on Android) is the home for thousands of users to manage, value, and trade their collections in real time. As we scale globally, we’re expanding our engineering team with world-class builders who want to own meaningful product surfaces and shape the future of fintech + marketplaces.

The Role: 

We’re looking for a Senior Fullstack Engineer, Frontend with deep React Native expertise to become one of the most senior engineers on our mobile team. You’ll own our flagship mobile experience end-to-end and play a critical role in the architecture, scalability, and performance of the app. This is a high-impact, high-visibility role: your work directly affects the core product experience that drives Alt’s growth. We’re looking for someone who isn’t just focused on closing tickets, but is deeply customer obsessed- driven to create delightful experiences and deliver meaningful value for the collectors and hobbyist who rely on Alt.

This role is ideal for someone who wants to shape technical direction, mentor other engineers, and eventually grow into team leadership/management as we scale.

You’ll also contribute to our React-based web application (roughly 70/30 frontend vs. backend, mobile-first).

What You’ll Do:

• Own Alt’s flagship mobile application our most important user-facing product.
• Lead the React Native platform across build systems, deployments (store and OTA), CI/CD, performance, reliability, and developer experience
• Work across multiple product domains:Auctions, Search, Payments, Lending, Notifications, Authentication, Fixed Price Marketplace and more.
• Build seamless, highly performant UIs that make a React Native app feel truly native.
• Work with the native layers (iOS & Android), bridging JavaScript and native code where needed.
• Partner closely with product, design, and business to influence what we build—not just how we build it.
• Mentor, level up, and provide architectural guidance to other engineers.
• Help us scale a global frontend/mobile team; grow into management over time if desired.
• Contribute to backend systems as needed (Python/FastAPI/Postgres, 30% of role).

• 5-7 years of professional experience building production React Native apps at scale.
• Experience shipping and maintaining ejected React Native applications.
• Ability to work with native iOS/Android code (Kotlin, Java, Swift, and Objective C), JavaScript/TypeScript, and build high-quality bridges between them.
• A strong product mindset: our engineers are highly product-focused and expected to have real influence.
• Experience making React Native apps feel extremely polished, smooth, and native.
• Background in fintech, marketplaces, gambling, hobby, or high-scale consumer mobile is a strong plus.
• Motivation to tackle hard engineering challenges across performance, architecture, and mobile infrastructure.
• Ability to work collaboratively in a fast-paced startup environment.

What You’ll Get From Us:

• A seat at the table to help shape the future of Alt and the alternative asset space
• Autonomy and ownership on projects that matter
• $100/month work-from-home stipend
• $200/month wellness stipend
• WeWork office stipend
• 401(k) retirement benefits
• Flexible vacation policy
• Generous paid parental leave
• Competitive healthcare benefits, including HSA, for you and your dependent(s)

Base salary range: $140,000-$180,000, plus equity. Offers may vary based on experience, location, and other factors.