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# Founding Frontend Engineer

- **Company:** Mozart AI
- **Location:** Greater London, UK
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, Databases, Digital Rendering, Continuous Integration, Next.js, Software Engineering, Data Streaming, WebGL, Three.js, ReactJS, Delivery Pipeline, Caching, Kotlin, HLSL, Build Tools, React Native, Front End Software Development, React Redux, Code Restructuring
- **Published:** August 30, 2026
- **Apply:** https://www.collegerecruiter.com/job/2822939273-founding-frontend-engineer

## About the Role

* React depth. You've architected and refactored large React codebases, including design systems, and understand React's internals and trade-offs beyond the API, * WebGL and canvas rendering (e.g., PixiJS, Three.js, shaders)
 * React Native (Expo), Swift, or Kotlin
 * Experience shipping consumer products -> you know how building for consumers differs from B2B
 * CRDT and multiplayer-state experience (e.g., Yjs, presence, conflict resolution)
 * Media-heavy or audio-streaming frontends
 * You make music - listening, exploring, producing. A big plus.
 * Experience working at an early stage startup or fast-paced environment. A big plus as well.

## Description

This is an intense, in-person role, built for people who want massive impact and grow their careers faster than anywhere else., * Own the delivery pipeline. CI/CD across web and mobile, feature flags and canary deploys -> users never run stale code against new APIs

 * Make production observable. Readable stack traces, useful errors, and monitoring that separates engineering signal from product analytics
 * Propose and lead the refactors that matter. Read the codebase, name the structural changes we need, and execute them with AI agents and the verification systems necessary
 * Own frontend testing. The right kind of test at every layer -> from component stories to visual canvas checks -> and lead our agentic end-to-end testing for the frontend
 * Ship product end-to-end. Real features with taste, instrumentation and fast iteration based on real user signal, * State management. You've designed production store architectures (e.g., Zustand, Redux, Jotai), kept state predictable at scale, and chosen the right update strategy for each operation
 * SSR in production. You've shipped and operated SSR (e.g., TanStack Start, Next.js) and understand hydration, streaming, caching, and framework trade-offs
 * Server-push architecture. You've build systems where the server reliably drives the client * background jobs finishing, collaborators acting, the database changing
 * Delivery infrastructure. Feature flags, canary deploys, CI/CD across platforms, and production-grade source maps
 * Refactor leadership. You read large codebases fast, identify the structural changes that matter, and lead migrations to completion, with AI agents as a daily tool
 * Testing judgment. You know a pure function, a store, a canvas renderer, and a user flow each deserve a different kind of test, you've implemented all at scale, including agentic E2E tests that run in CI
 * Agent-native. You think in agentic workflows and build software that is operable and verifiable by agents, not just humans
 * Truth seeker. You talk to users, watch sessions, and read analytics -> chasing what users need, not what you assume
 * Product taste. You have strong opinions about motion, sound, and feel, and can defend design decisions on their merits
 * High ownership, low ego. You ship fast, own outcomes after release, and do whatever needs doing
 * 5+ years of professional experience


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