Full Stack Engineer (Mobile-first)

About Sierra Studio

When you apply to Sierra, you join an ecosystem. We specialize in connecting talented Brazilian professionals with exciting career opportunities in a highly-vetted small community of growing companies in the US. Applying to Sierra seamlessly integrates you into this ecosystem, granting automatic eligibility for all relevant opportunities we offer.

About Our Hiring Partner

Our hiring partner is building attribution infrastructure for creator commerce. Creators lose billions annually because 80% of purchases happen offline where traditional tracking fails, browser extensions hijack affiliate links (see: Honey lawsuits), and cross-device journeys break cookie-based attribution.

They use card-linking technology (Plaid/Fidel) to track actual purchase behavior. When a creator's fan links their card once, they attribute every purchase they make - online, offline, across all devices - enabling creators to earn from lifetime customer value instead of just last-click conversions.

Location: Remote

Type: Full-time Contract

Stage: Pre-seed, MVP in development

The Role

Our hiring partner is looking for a Full-Stack Mobile Engineer to help grow and evolve their mobile app. You'll focus primarily on building delightful user experiences while having the flexibility to make backend changes when needed. This is a frontend-leaning full-stack role where you'll own features end-to-end—from UI to API.

You'll build and maintain their mobile applications (React Native) and integrate third-party platforms that power creator rewards. You'll also monitor and optimize their transaction attribution system to ensure accurate, reliable processing at scale.

What You'll Do

Mobile Applications (Primary Focus):

- Build and improve mobile app features – Create polished, performant UI components and screens that users love from scratch

- Own features end-to-end – Take a feature from design to shipped, including any necessary API changes

- Extend backend APIs – Add endpoints or modify existing ones to support new mobile features

- Write tests – Maintain code quality with unit and integration tests

- Implement responsive designs – Build interfaces that work beautifully across all device sizes

- Collaborate with design – Work closely with designers to bring mockups to life with attention to detail

- Deep linking – from social platforms (Instagram, TikTok) → app → offer activation

- Push notifications – for reward milestones and transaction updates

- Authentication flows – with biometric support

- Offline-first architecture with sync

- Mobile-optimized reward discovery and redemption flows

- App store deployment (TestFlight, Google Play)

Third-Party Integrations:

- Discord (role-based rewards, community access)

- Patreon (membership tier verification)

- Whop (digital product access)

- Event platforms: Posh, Luma, Eventbrite (ticketing, reservations)

- Social APIs: Instagram, TikTok, YouTube (follower verification, analytics)

- OAuth flows, webhook handlers, retry logic, rate limiting

Bonus - Transaction Attribution Monitoring:

- Monitor Plaid webhook processing and attribution accuracy

- Debug edge cases: refunds, duplicate transactions, merchant mismatches

- Optimize real-time reward progress updates

- Maintain fraud detection patterns

- Improve attribution logic based on production data

Required Skills

Must-Haves:

- 4+ years building production applications

- Mobile development experience (React Native/Expo preferred OR native iOS/Android)

- Strong TypeScript/JavaScript proficiency

- Experience with deep linking (Universal Links, App Links, deferred deep links)

- Third-party API integration experience (OAuth, webhooks, REST)

- App store deployment experience (TestFlight, Google Play)

- Node.js backend familiarity (for API integration work)

- Understanding of mobile-specific patterns (push notifications, offline sync, secure storage)

Nice-to-Haves:

- Consumer app experience (social, rewards, loyalty programs)

- Fintech API experience (Plaid, Stripe, payment processing)

- Experience with Discord bots, Patreon API, social platform APIs

- Understanding of creator economy or influencer marketing

- E-commerce or attribution systems knowledge

- Experience building from 0-to-1 on mobile

Tech Stack

Mobile: React Native (Expo), TypeScript, React Navigation, React Query

Backend (Integration): Node.js, Express, TypeScript, PostgreSQL, Plaid SDK

Infrastructure: Git/GitHub, AWS, Firebase (push notifications)

Tools: Linear, Figma, Postman

What You'll Bring

- Mobile-first development mindset

- Track record of shipping mobile apps to production

- Ownership mentality - you define solutions and drive implementation

- Strong debugging skills and attention to detail

- Excellent communication and ability to articulate technical trade-offs

- Comfortable working independently in fast-paced startup environment

- Interest in creator economy, commerce, or consumer fintech

Compensation & Benefits

- Salary Range: $60,000 - $90,000 annually

- Four weeks PTO per year plus all national holidays

- Fully remote position with flexible work arrangements

- Equity packages available as the company moves from pre-seed to seed stage