Fullstack Mobile Developer

Senior Full-Stack Mobile Developer

• Salary: $50/hour on B2B
• 100% Remote

We're looking for a Senior Full Stack Mobile Developer for an international technology group delivering large-scale digital solutions to the financial sector. Their engineering organization is moving toward smaller teams with broader ownership, more code sharing across mobile platforms, and pragmatic use of AI in everyday development. You'd join the group behind customer-facing banking products - working across the app itself, the logic shared between mobile platforms, and the services and infrastructure that power it.

Working stack: Kotlin, Kotlin Multiplatform, Java, Spring Boot, AWS, Kafka.

A senior individual contributor role with real end-to-end scope. You'll carry features from technical design through release and production support, and help shape how mobile architecture and shared code evolve across the team.

Requirements

• Solid track record of shipping production mobile applications, with a deep grasp of Android and iOS architecture components
• Advanced Kotlin skills and command of modern mobile architecture patterns
• Hands-on backend development with Java 7+ (or Kotlin) and Spring Boot, building REST APIs
• Familiarity with microservices, distributed systems, and event-driven design
• Practical experience with CI/CD, automated testing, and operating production systems
• Comfort owning a feature end-to-end - from design through deployment and beyond
• Strong communication skills and experience collaborating across product, design, security, and platform teams
• Day-to-day use of AI coding assistants (Copilot, Cursor, Claude Code, or similar), paired with critical review of generated output for quality, security, and performance
• Fluent written and spoken English

Nice to Have

• Kotlin Multiplatform in production - a strong advantage
• Flutter or React Native background, with willingness to pick up KMP
• Kafka or comparable event-streaming technologies
• AWS or another major cloud platform
• Fintech, banking, payments, or other regulated-industry experience
• Apple Pay, Google Pay, or wallet/payment integrations
• Modular mobile architecture or shared SDKs/libraries
• Observability, performance profiling, and production incident analysis
• Experience working with specs, examples, and tests as the driver of implementation

Key Responsibilities

• Design, build, and refine mobile features used by a large customer base
• Develop shared cross-platform business logic, primarily with Kotlin Multiplatform
• Build and maintain backend services and APIs in Java/Kotlin with Spring Boot
• Contribute to cloud infrastructure, delivery pipelines, monitoring, and production support
• Apply AI tooling across the development lifecycle - code, tests, documentation, debugging - while holding a high bar for quality, security, and maintainability
• Collaborate closely with product, design, architecture, security, and platform teams
• Mentor other engineers and help define team-wide engineering practices
• Continuously improve performance, reliability, security, and user experience