Senior Full Stack Mobile Engineer (Web3 & Fintech) at Crush

The Mission

Crush Rewards is building the ultimate bridge between traditional consumer behavior and the decentralized future. We’re not just another rewards app; we’re a contribution network where everyday actions—like scanning a receipt and linking credit card spending—are transformed into on-chain value.

We are looking for a Full Stack Mobile Engineer who thrives at the intersection of high-performance mobile interfaces, robust backend architecture, and the Solana blockchain. You will own features end-to-end: from crafting a "buttery-smooth" UI to architecting the backend pipelines that verify financial data and trigger token emissions.

What You’ll Do

Architect the Frontend: Lead the development of our React Native (Expo) app, ensuring high-performance execution of complex features like real-time token charts and deep-linked wallet interactions.
Build Robust Backend Pipelines: Own the Node.js/Express API that powers our ecosystem. You'll manage critical backend logic including receipt OCR verification, transactional syncs with credit cards, product rewards calculations, and user progression systems (streaks, levels, milestones).
Execute Web3 Strategy: Implement and scale our Solana integration. You will manage custodial wallet flows with Crossmint, execute on-chain token swaps via Jupiter, and handle complex staking/unstaking logic.
Own the Data Lifecycle: Manage a scalable PostgreSQL architecture, ensuring real-time data consistency across user profiles, streaks, and transaction histories.
Iterate with Quality: Advocate for best practices in TypeScript, automated testing, and CI/CD (EAS/GitHub Actions) to ensure we ship high-quality code to the App Store and Play Store multiple times a week.
Drive Growth through Data: Use PostHog analytics and OneSignal engagement tools to understand user behavior and build the features that keep our users "Crushing" their goals.

What You’ll Need

The TypeScript Professional: You have 4+ years of experience in professional software engineering, with a mastery of TypeScript across the entire stack.
Mobile Expertise: Deep experience with React Native (Expo). You understand the mobile lifecycle, performance optimization, and how to build responsive UIs using modern toolkits.
Backend Proficiency: Strong experience with Node.js and PostgreSQL. You know how to design clean APIs and manage complex relational data at scale.
Web3 Literacy: You are comfortable with the Solana ecosystem (web3.js, SPL tokens). You understand how to interact with smart contracts and manage the security implications of blockchain transactions.
Fintech Experience: Practical experience integrating third-party financial APIs and handling sensitive user data with a "security-first" mindset.
Product Intuition: You care about the "Why" behind a feature. You can translate a Figma design into a functional reality while suggesting improvements to the user flow. Bonus points if you can create clean UI components without Figma.

Our Tech Stack

Mobile: React Native, Expo, TypeScript.
Backend: Node.js, Express, PostgreSQL, Edge Functions.
Blockchain: Solana (Web3.js), SPL Tokens, Crossmint, Jupiter SDK.

Bonus Points

You’ve built or contributed to a Solana Anchor program (Rust) and/or typescript SDKs.
Experience with AI/LLM pipelines for data extraction or personalized user experiences.
Background in a high-growth startup where you wore multiple hats and "owned" the outcome.
A passion for the "Rewards" space and an understanding of gamification mechanics (streaks, levels, milestones).

Why Join Us?

At Crush Rewards, we're a small, focused team where every member has significant impact and ownership. You won't just be a "cog in the machine"—you will be the architect of a platform that redefines how millions of people interact with their money and the blockchain. We value clean code, fast iteration, and a relentless focus on the user experience.

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