Senior Full-Stack Mobile Engineer

Senior Full-Stack Mobile Engineer
We’re looking for a senior, hands-on engineer to take ownership of the technical development of an existing mobile-first consumer product.
The product includes user accounts, points, rewards, progression mechanics, transactional logic, notifications, admin-controlled rules, and backend workflows. We need someone who can understand the existing system quickly, work directly with the founder, and independently translate product feedback into reliable technical implementation.
This is a hands-on engineering role. You will be expected to own features, bugs, backend logic, integrations, testing, and releases rather than simply execute isolated tickets.
Responsibilities
• Take ownership of the existing mobile and backend codebase.
• Build, maintain, and improve features across the mobile application and backend.
• Implement and maintain points, rewards, balances, earning rules, redemption logic, eligibility rules, limits, and related user progression mechanics.
• Ensure points and rewards calculations are accurate, consistent, and protected against duplicate transactions, race conditions, abuse, and edge cases.
• Build and maintain transaction histories, activity logs, reward states, and user-facing balance updates.
• Implement backend rules that may vary based on user actions, campaigns, reward types, or admin-defined conditions.
• Develop and maintain flows involving authentication, user profiles, referrals, notifications, analytics, payments, and third-party APIs where required.
• Build or maintain admin functionality used to manage rewards, points rules, campaigns, user states, and product configuration.
• Translate founder feedback, product requirements, and UX changes into production-ready implementation.
• Investigate and fix bugs across frontend, backend, database, and integration layers.
• Identify technical issues in the existing architecture and improve reliability, scalability, security, and maintainability where necessary.
• Maintain proper database structures, API contracts, validation, and error handling.
• Handle mobile builds, deployment, and releases for iOS and Android.
• Maintain clean Git workflows and proper version control.
• Test features thoroughly before delivery, including edge cases and failure scenarios.
• Communicate technical risks, dependencies, and trade-offs clearly before implementation.
What we’re looking for
• Strong professional experience building and shipping production mobile applications.
• Strong full-stack development experience across mobile, backend, APIs, and databases.
• Experience building systems involving points, credits, rewards, wallets, loyalty mechanics, gamification, or other transaction-based user systems.
• Strong understanding of transactional integrity and data consistency.
• Experience designing logic where balances or rewards must not be duplicated, lost, or incorrectly calculated.
• Strong experience with APIs, authentication, databases, notifications, and backend services.
• Strong debugging skills across the entire stack.
• Ability to work confidently inside an existing codebase.
• Ability to understand business rules and convert them into robust technical logic.
• Comfortable working independently with minimal supervision.
• Strong ownership mentality and attention to detail.
• Experience releasing apps to the Apple App Store and Google Play Store.
• Comfortable with Git and modern development workflows.
The ideal candidate
You should be comfortable receiving product feedback such as:
“A user should earn points after completing this action, but only once under these conditions. The balance should update immediately, the transaction should be logged, the reward should unlock at the correct threshold, and admins should be able to change the rule later.”
You should be able to investigate the current implementation, understand the business logic, identify technical dependencies and edge cases, implement the change across the required parts of the stack, test it properly, and deliver a stable solution.
We are specifically looking for someone who takes responsibility for the integrity of the system, not someone who simply closes tickets.
The Stack:
React Native + Expo SDK 54
TypeScript 5.9.2
Expo Router (file-based routing)
TanStack React Query v5
Supabase
Lucide React Native (icons)
Role structure
You will work directly with the founder.
The founder will provide product direction, priorities, feedback, feature requirements, and expected behavior. You will be responsible for deciding how those requirements should be implemented technically and for maintaining the overall quality and stability of the codebase.
This role can begin as freelance / contract-based, with the potential to develop into a longer-term engagement and company shares.

Work arrangement
Yes