Mobile UI Engineer

About us

We're a stealth-stage, real-time group payments platform built with Kotlin Multiplatform, focused on making shared expenses seamless across dining, travel, events, and everyday group spending. The product combines automated expense splitting, real-time payment coordination, and flexible payment options in a single mobile experience.

Our shared UI platform powers iOS, Android, and desktop from a single Compose Multiplatform codebase containing 280+ Kotlin files and 85+ production screens.

What you'll own

Cross-platform product development

• Build and maintain production-ready mobile experiences across iOS and Android from a shared Kotlin codebase

• Own feature development from API integration through polished UI delivery

• Help scale a rapidly evolving product focused on real-time expense coordination and payments

UI architecture

• Develop screens, state management flows, navigation patterns, and reusable UI components

• Maintain clean boundaries between presentation logic, domain logic, and backend-generated models

• Contribute to shared component systems and internal UI tooling

API and realtime integrations

• Integrate GraphQL-backed product features, mutations, caching, and optimistic UI updates

• Build realtime user experiences driven by live transaction and payment updates

• Collaborate closely with backend engineers on API evolution

Platform integrations

• Maintain integrations with native mobile capabilities including authentication, deep linking, push notifications, sharing, and contacts

• Ensure consistent behavior across iOS and Android targets

Product velocity

• Ship quickly in a fast-moving startup environment with frequent mobile releases

• Participate in architecture reviews, feature planning, and technical direction

• Help maintain development standards, CI reliability, and long-term scalability

Required experience

Kotlin

• 3+ years of production Kotlin experience

• Strong understanding of coroutines, Flow, state management, and modern Kotlin patterns

Jetpack Compose or Compose Multiplatform

• Production experience building complex reactive UIs

• Comfortable explaining recomposition, state derivation, side effects, and performance tradeoffs

API-driven applications

• Experience integrating GraphQL or similar strongly typed API systems

• Familiarity with realtime or event-driven application patterns

Architecture and tooling

• Experience with dependency injection and modular application architecture

• Comfortable working in large shared codebases with CI/CD workflows

Nice to have

• Kotlin Multiplatform experience across iOS and Android

• Experience with realtime applications or fintech products

• Experience maintaining a shared design system or component library

• Familiarity with startup product environments and rapid iteration cycles

How this role works day-to-day

We operate with a strongly opinionated architecture designed for long-term maintainability and fast iteration. Mobile engineers are expected to think carefully about ownership boundaries, scalability, and developer ergonomics, not just feature delivery.

The team ships quickly and collaboratively. Mobile, backend, and product decisions are tightly integrated, and engineers are expected to move comfortably between UI implementation, API discussions, and architecture decisions.

You'll be joining at a stage where the platform is already substantial in scope, but still early enough to have major influence over product direction, engineering standards, and the future of the system.