Senior Mobile Engineer (React Native / iOS)

Location: Remote/Hybrid - Pakistan

Position: Senior Mobile Engineer (React Native & iOS)

Company: Roll2Rell

Reports to: Founder / Head of Engineering

Note: This hiring is for Roll2Reel. Please read the complete job description carefully before applying. If your experience and skills align with the requirements of the role, we encourage you to apply.

Who we are

We're building a new iOS app that turns the videos already sitting in your camera roll into publishable short-form content in about sixty seconds.

Creators have hundreds of raw clips and no time to edit. Our answer is templates extracted from content that already worked: you share a viral reel into the app, and it reverse-engineers the structure scene boundaries and cut timing, caption placement and styling, music beat alignment, whether it's a talking-head or a split-screen. It then fills that template with your footage, matched semantically from your own library, hands you an editor to refine it, and exports straight back to social.

The hard part is that almost all of this runs on the phone.

To search your camera roll by meaning ("me at the gym", "coffee shop b-roll") we embed your entire video library on-device using a compact vision-language model running on the Apple Neural Engine - keyframe-only decode, zero-copy into CoreML, indexed into SQLite and a local vector index. Template extraction OCR, scene detection, beat detection, audio classification - also runs on-device through native Swift modules. That's a deliberate architectural bet: no per-user server GPU cost, no uploading a creator's private video, and instant feedback. It also means performance engineering and UX validation are the product, not a nice-to-have - we've cut our on-device sync pipeline runtime by more than 75% through exactly this kind of work.

Around that sits a large TypeScript monorepo with a fully typed tRPC API, Drizzle/Postgres on Supabase, a personalised recommender, a web app on Cloudflare Workers serving marketing, checkout and our internal admin dashboard, and provider configuration managed as code across many external services. You'd be joining to own the surface creators actually touch

How we work

We ship continuously and care a lot about craft - this is a video editing app, so animation smoothness, gesture feel, thermal behaviour and cold-start time are product requirements, not polish. We lean hard on AI-assisted development (Claude Code, Cursor) as a normal part of the workflow, not an experiment. We practise trunk-based development: main always reflects what is live in production. We document decisions properly the codebase carries extensive engineering notes explaining why things are the way they are, and we expect contributors to maintain that standard. We operate with high autonomy, direct feedback, and real ownership.

What you will do

You'll work closely with the founding team to build the app's mobile experience, taking on increasing system ownership as you ramp up.

• Build the app: Architect and ship features across the Expo / React Native app - the video editor, the discovery feed, onboarding, the export flow - with a genuine eye for interaction quality and feel.
• Go native when it matters: Write and maintain Swift native modules (via Nitro/Nitrogen) for the work JavaScript can't do: CoreML inference, video frame extraction, audio analysis, PhotoKit integration.
• Own performance & UX quality: Profile and optimise on-device ML throughput, memory, thermal behaviour and battery. Diagnose the difference between an ANE and a GPU execution path and know which one wins.
• Instrument, profile, and act: Use Xcode Instruments, React Native profiling tools, PostHog, Sentry and Grafana to optimize performance, validate UX, understand real device behaviour and close the loop on what you ship.
• Work across the stack: Extend tRPC procedures, model Drizzle/Postgres schemas, and write migrations you won't be blocked waiting on a backend engineer.
• Release pipeline & system ownership: Support and gradually take ownership of EAS builds, OTA updates, TestFlight, App Store submissions, and the version-gating that keeps older installs compatible with the live API as you settle into the codebase

What we're looking for

• An experienced mobile engineer: 5+ years shipping production mobile software, with React Native / Expo apps live in the App Store that you can point to.
• Deep TypeScript and React: Strong command of the modern ecosystem - hooks, state management (Zustand, TanStack Query), and the performance characteristics of React Native specifically.
• Real native iOS ability: Comfortable in Swift and Xcode. You can read a native crash log, write a native module, and debug across the JS native bridge. You don't treat the native layer as someone else's problem.
• Performance & UX QA focus: Hands-on experience with native and React Native profiling tools (Xcode Instruments, etc.) to optimize frames, memory, and thermal load, along with a keen eye for validating UX quality. You've profiled a slow app and made it fast.
• Comfortable server-side: Postgres data modelling, an ORM (Drizzle ideal), and typed API design (tRPC ideal).
• Product-obsessed: You think like a creator using the app. You notice a janky drag or a 200ms delay and you care.
• High-agency & strong writer: You can take a loose goal, clarify it, unblock yourself, and land it. Clear written communication in English. We make decisions in writing and expect you to argue your position well. AI-fluent: You already use AI tooling to move faster and have opinions about where it helps and where it doesn't.

Bonus points

• On-device ML experience CoreML, ONNX, Core ML Tools, quantisation, Apple Neural Engine.
• Video or audio engineering - AVFoundation, Skia, FFmpeg, codecs, frame-accurate editing.
• Vector search / embeddings (pgvector, USearch, HNSW).
• Mobile subscriptions and IAP (RevenueCat, StoreKit) and attribution (AppsFlyer).
• Experience mentoring engineers or leading a small team.

Our stack

• Mobile: Expo SDK 53, React Native 0.79, expo-router, TypeScript, React Native Skia, Reanimated, Nitro Modules (Swift), opsqlite, NativeWind, Zustand, TanStack Query
• On-device ML: CoreML (on-device vision + beat-detection models), Apple Neural Engine, USearch Backend: tRPC, Drizzle ORM, Postgres + pgvector (Supabase), Next.js on Vercel, Python/Flask for embeddings
• Web: TanStack Start on Cloudflare Workers, Tailwind, Stripe
• Infra & tooling: pnpm + Turborepo monorepo, EAS, GitHub Actions, GCP Secret Manager, PostHog, Sentry, Grafana, Xcode Instruments, RevenueCat, AppsFlyer

Why join

Genuinely hard problems: On-device machine learning, real-time video rendering, and semantic search over a user's private media library on a phone, on a thermal budget. This is not CRUD.

A surface that matters: The mobile app is the product. What you build is what users experience.

Senior scope & modern codebase: Direct access to founders, architectural decisions, and a fully typed, heavily documented monorepo with proper CI/CD. You'll spend your time building, not archaeology. Competitive compensation: We offer a competitive compensation package.