Remote Flutter Engineer - DeFi Wallets & On-Chain Apps

KAST; New York (NY); On-site; USD 120,000 - 180,000; Full time

Job summary

KAST is seeking a mid-level to senior Flutter engineer who understands DeFi to build end-to-end consumer DeFi products. You will translate on-chain flows into clear mobile UX, collaborate with backend, product, and design to ship secure money-movement features, and own wallet and transaction states.

Ideal candidates have 2+ years of Flutter experience (or 3+ years with shipped apps) and hands-on DeFi experience across lending, staking, swaps, or wallets. Remote work from the US is supported.

Qualifications

• 2+ years of production mobile development with Flutter or 3+ years with shipped apps.
• Hands-on DeFi experience with on-chain protocols (lending/borrowing, staking, swaps, wallets).
• Strong Flutter fundamentals: state management, navigation, clean architecture, DI.
• Experience consuming REST APIs and managing complex asynchronous and multi-step transaction flows.
• Mobile security best practices and secure storage; MFA flows.
• Git-based workflows, code review, and app store deployment.

Responsibilities

• Build and own consumer-facing DeFi features in the KAST mobile app, end to end.
• Translate DeFi concepts into clear, trustworthy mobile UX.
• Integrate with backend services and handle multi-step money-movement transactions.
• Handle wallet, signing, and transaction states with robust error handling and user feedback.
• Contribute to a clean, well-tested mobile architecture and components.
• Write testable code and participate in code reviews and releases.
• Collaborate with product and design to shape requirements into shipped features.

Skills

Flutter

Mobile development

DeFi experience

REST APIs

Security best practices

Git workflows

Tools

Flutter SDK

Dart

CI/CD

Job description

KAST is seeking a mid-level to senior Flutter engineer who understands DeFi to build end-to-end consumer DeFi products. You will translate on-chain flows into clear mobile UX, collaborate with backend, product, and design to ship secure money-movement features, and own wallet and transaction states.

Ideal candidates have 2+ years of Flutter experience (or 3+ years with shipped apps) and hands-on DeFi experience across lending, staking, swaps, or wallets. Remote work from the US is supported.