Senior Mobile Engineer - React Native & Expo

TRIUMPH; San Francisco (CA); On-site; USD 150,000 - 210,000; Full time

Job summary

Triumph is building Rips, a collectibles trading card app for mobile. You will own core features in React Native and Expo, shipping thoughtful UX and high polish from design through launch. You’ll work closely with backend engineers on API design, chase performance goals, and shape the architecture that enables teammates to move quickly.

This is hands-on, end-to-end ownership in a small, fast team. You’ll operate in a lean environment where the person who designs a feature also ships it and owns

Qualifications

• Strong mobile engineering background with React Native and Expo preferred.
• Own consequential work: ship features you designed and maintain them.
• Deep platform understanding of device behavior beyond UI components.
• Craftsmanship and polished interactions for native-feeling UX.
• Ability to architect and set guardrails for teams to move quickly.
• Familiarity with AI as a tool; able to explain every line shipped.
• In-person collaboration required at Triumph's headquarters in San Francisco.

Responsibilities

• Build and own core product features in React Native and Expo from design through launch and iteration.
• Care about motion, gesture, transitions, perceived performance, and details that impact daily usage.
• Dive into native modules, platform APIs, rendering behavior, and build configuration when needed.
• Collaborate with backend engineers on API and data model design, advocating for strong contracts.
• Ensure performance and reliability: startup time, frame rate under load, crash-free sessions.
• Contribute patterns and architecture that empower mid-level and junior engineers to move fast.

Skills

React Native

Expo

Mobile engineering

Ownership

Native iOS/Android

Performance

Architecture

AI fluency

Collaboration

Job description

Triumph is building Rips, a collectibles trading card app for mobile. You will own core features in React Native and Expo, shipping thoughtful UX and high polish from design through launch. You’ll work closely with backend engineers on API design, chase performance goals, and shape the architecture that enables teammates to move quickly.

This is hands-on, end-to-end ownership in a small, fast team. You’ll operate in a lean environment where the person who designs a feature also ships it and owns