Senior Flutter Engineer - DeFi Mobile Apps

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

Job summary

Kast.xyz is seeking a mid-level to senior Frontend Developer (Flutter; DeFi) to build consumer DeFi features for our mobile app. You will translate complex on-chain flows into clear UX and collaborate with backend, product, and design to ship money-movement features that are secure and reliable.

Location: remote from the US. Required: 2+ years Flutter, hands-on DeFi experience, strong Flutter fundamentals, REST APIs, mobile security, and Git workflows.

Qualifications

• 2+ years of production mobile development with Flutter, or 3+ years with ownership of shipped consumer apps.
• Hands-on DeFi experience—on-chain protocols and concepts like collateral, LTV, health factor.
• Strong Flutter fundamentals: state management, navigation, clean architecture, dependency injection.
• Experience consuming REST APIs, handling auth tokens, and multi-step transaction flows.
• Mobile security best practices: secure storage, MFA, and sensitive data handling.
• Git-based workflows, code review, and shipping to app stores.

Responsibilities

• Build and own consumer-facing DeFi features end to end in the Kast mobile app.
• Translate DeFi concepts into clear, trustworthy mobile UX.
• Integrate with backend services for secure money-movement and transaction flows.
• Handle wallet, signing, and transaction states with robust user feedback.
• Contribute to a clean, well-tested mobile architecture and shared component patterns.
• Write testable code and participate in code review and release quality.
• Collaborate with product and design to shape requirements into shipped features.

Skills

Flutter mobile development

DeFi experience

REST APIs

Mobile security

Git workflows

Tools

Git

CI/CD pipelines

Job description

Kast.xyz is seeking a mid-level to senior Frontend Developer (Flutter; DeFi) to build consumer DeFi features for our mobile app. You will translate complex on-chain flows into clear UX and collaborate with backend, product, and design to ship money-movement features that are secure and reliable.

Location: remote from the US. Required: 2+ years Flutter, hands-on DeFi experience, strong Flutter fundamentals, REST APIs, mobile security, and Git workflows.