Flutter Developer with DeFi Expertise

Overview

KAST is seeking an experienced mid-level to senior Flutter developer specialized in Decentralized Finance (DeFi) to join their engineering team remotely from the US. This role focuses on creating end-to-end consumer-facing DeFi features for the KAST mobile app, ensuring complex on-chain financial processes—such as lending, staking, swaps, savings, and self-custody wallets—are translated into intuitive, secure, and engaging interfaces.

Key Responsibilities

• Develop and maintain DeFi functionality in the mobile app with full ownership.
• Convert intricate DeFi concepts like lending, swapping, and borrowing into clear and reliable user experiences.
• Integrate backend services securely, managing multi-step transactions and authorization workflows.
• Manage wallet states and transaction statuses including handling errors and providing real-time user feedback.
• Contribute to a well-structured, tested mobile app architecture with reusable components.
• Produce maintainable, testable code, actively participate in code reviews and assurance of release quality.
• Work collaboratively with product and design teams to deliver feature requirements effectively.

Qualifications

• Minimum 2 years of Flutter development experience in production or 3+ years owning shipped consumer applications.
• Demonstrated hands-on involvement with DeFi protocols on-chain such as lending/borrowing, staking, swaps, or wallets, with understanding of financial terms like collateral, loan-to-value ratios, health factor, and network fees.
• Strong proficiency in Flutter core principles including state management, navigation, clean architecture, and dependency injection.
• Experience with RESTful APIs, authentication token handling, and managing asynchronous transaction flows.
• Deep understanding of mobile security best practices like secure storage, sensitive data protection, and multi-factor authentication.
• Familiarity with version control via Git, peer code review processes, and app deployment on App Store and Play Store.

Additional Preferred Skills

• Prior experience integrating DeFi lending, staking, or swapping protocols on major blockchain platforms.
• Knowledge of embedded or MPC wallet solutions or self-custody key management.
• Background in fintech, neobanking, or regulated financial services.
• Usage of mobile analytics tools, observability platforms, and continuous integration/deployment (CI/CD) pipelines.
• Contributions to shared Flutter libraries or modular multi-app projects.