Frontend Developer (Flutter; DeFi)

As a mid-level to senior Flutter engineer at KAST, you'll build consumer-facing DeFi products end to end. You understand how DeFi products-lending, staking, swaps, savings, and self-custody wallets-actually work on-chain, and you translate complex on-chain flows into interfaces that are clear, trustworthy, and delightful. You collaborate closely with backend, product, and design to ship money-movement features that are secure and reliable.

What you'll do

• Build and own consumer-facing DeFi features in the KAST mobile app end to end
• Translate DeFi concepts such as lending, swap, and borrowing into clear, trustworthy mobile UX
• Integrate with backend services and handle secure, multi-step money-movement and transaction authorization flows
• Handle wallet, signing, and transaction states (pending, submitted, confirmed, failed) with robust error handling and user feedback
• Contribute to a clean, well-tested mobile architecture and shared component patterns
• Write testable, maintainable code and participate in code review and release quality
• Collaborate with product and design to shape requirements into shipped features

What you bring

• 2+ years of production mobile development with Flutter, or 3+ years with ownership of shipped consumer apps
• Hands-on DeFi experience: you have built, integrated, or worked closely with on-chain protocols (lending/borrowing, staking, swaps, or wallets) and understand concepts like collateral, LTV, health factor, and gas/network fees
• Strong command of Flutter fundamentals: state management, navigation, clean architecture, and dependency injection
• Experience consuming REST APIs, handling auth tokens, and managing complex asynchronous and multi-step transaction flows
• A solid understanding of mobile security best practices (secure storage, sensitive data handling, MFA flows)
• Comfort with Git-based workflows, code review, and shipping to the App Store and Play Store

Nice to have

• Experience integrating with DeFi lending, staking, or swap protocols on any major chain
• Familiarity with embedded/MPC wallet providers or self-custody and key import-export flows
• Experience in fintech, neobanking, or regulated financial products
• Exposure to mobile analytics/observability and CI/CD
• Contributions to shared Flutter packages or a modular multi-app codebase

About KAST

KAST builds consumer-facing DeFi products, helping users access lending, staking, swaps, and self-custody wallets through a mobile-first experience.