Senior Frontend - Mobile Engineer

Build the mobile experience that makes Usual feel like a neobank — not a DeFi app.

You will own the mobile app end-to-end: from wallet connection flows and transaction signing to real-time balance displays and cross-chain account views.

The product you build will be the first thing most users touch. It must be fast, reliable, secure, and correct when handling real money.
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Core Responsibilities
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1. Mobile App Development

• Build and maintain a cross-platform React Native app (iOS and Android) in TypeScript.
• Translate Figma designs into pixel-accurate, performant UI components.
• Manage App Store and Google Play release pipelines, including versioning and review cycles.
• Optimize rendering performance, bundle size, and startup time, especially for low-end devices.
• Implement or assist with deep linking and push notification flows.

2. Web3 and Wallet Integration

• Integrate in-app wallet generation and linking flows using Privy for authentication.
• Configure the client for gasless transactions using ERC7702 and ERC4337 account abstraction.
• Handle the full EVM transaction lifecycle: crafting, simulating, gas estimating, signing, broadcasting, confirming, and failure recovery.
• Interact securely with Usual and third-party smart contracts, with proper slippage controls, MEV protection, and least-privilege approvals.
• Read and interpret Solidity contracts to understand interfaces, data structures, and events without relying on the smart contract team.

3. Data and State Management

• Consume on-chain data efficiently using viem and wagmi while optimizing RPC usage.
• Query existing Subgraphs via The Graph and help define requirements for new ones.
• Implement real-time responsiveness for balances, yields, and transaction history.
• Manage local application state across products, chains, sessions, and wallets.
• Collaborate with backend teams on APIs to persist user data where required.

4. UX Reliability and Edge Cases

• Implement optimistic UI patterns while safely handling stuck transactions, reverts, and delays.
• Handle wallet switching, disconnection, and reconnection with clear user feedback.
• Support seamless multi-chain interactions across Ethereum, Arbitrum, Base, and BNB.
• Ensure correct app behaviour during RPC or Subgraph lag and network degradation.
• Write unit and integration tests for core financial flows such as deposits, withdrawals, and yield claims.

5. Observability and Quality

• Integrate crash reporting and performance monitoring tools (e.g., Sentry).
• Define and track mobile-specific SLAs, including launch time, data freshness, and failure rates.
• Maintain internal documentation for component architecture and key user flows.
• Participate in code reviews, focusing on security and correctness for financial operations.
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Expected Outcomes

• A production-grade mobile app shipped and maintained on both App Store and Google Play.
• Reliable account-abstracted Web3 transaction flows across all supported chains.
• Real-time account views with accurate balances, yields, and transaction history.
• Zero critical regressions or security incidents affecting financial flows.
• A documented component library and flow diagrams stored in the internal knowledge base.
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Candidate Profile

Must Have

• 5+ years of mobile development experience, including 3+ years with React Native in TypeScript.
• Experience integrating Privy, WalletConnect, or similar SDKs with wagmi in production.
• Experience shipping apps to the App Store and Google Play, including handling review processes.
• Experience building complex smart contract interactions, such as multi-hop swaps or transaction bundling.
• Strong understanding of the EVM transaction lifecycle (signing, gas, nonce management, failure modes).
• Comfortable reading Solidity contracts to understand what data to query and how.

Nice to Have

• Experience with ERC7702 or ERC4337 account abstraction for gas sponsorship.
• Experience working at a DeFi protocol, stablecoin platform, or consumer fintech app.
• Native iOS (Swift) or Android (Kotlin) development experience alongside React Native.
• Background in financial products where correctness and uptime are critical.
• Experience querying Subgraphs via The Graph client-side.
• Experience with async data fetching patterns such as TanStack Query.
• Experience with state management at scale (Zustand, Redux Toolkit, or similar).
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Attributes We Value

User-Obsessed
Understands that UX in financial apps is a trust signal, not just polish.

Security-Conscious
Never stores sensitive data client-side and handles signing flows with least-exposure principles.

Autonomous
Able to own a feature end-to-end, from specification to App Store release.

Detail-Oriented
Catches subtle issues, such as failed transactions incorrectly appearing as pending.

Far-Sighted
Anticipates future needs and surfaces actionable improvements before they become blockers.

Collaborative
Actively reviews PRs and provides clear feedback that improves team velocity.

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