Senior Full Stack Mobile Developer

Nix; Boston (MA); Hybride; USD 120 000 - 160 000; Plein temps

Avantages offerts par ce poste

Flexible working format

Competitive salary

Career growth

Professional development tools

Active tech communities

Education reimbursement

Anniversary presents

Corporate events

Résumé du poste

N-iX in Boston is seeking a Senior Full Stack Mobile Developer to join Clint's team. You will build mobile features end-to-end and contribute backend services, APIs, and cloud components for scalable fintech applications.

Bring strong mobile experience, Kotlin Multiplatform preferred, plus Java/Kotlin with Spring Boot knowledge. You will mentor others, shape engineering practices, and collaborate across product, design, security and platform teams to deliver high-quality software.

Qualifications

• Proven mobile app development experience.
• Strong Kotlin skills and modern mobile architecture.
• Kotlin Multiplatform experience preferred but not required.
• Backend experience with Java 7+ and Spring Boot.
• Experience with APIs, microservices and cloud services.
• Experience with CI/CD, automated testing and production systems.
• Ability to own a feature from design to production.
• Strong communication and cross-team collaboration.

Responsabilités

• Build and improve mobile features used by real customers.
• Develop shared mobile logic using Kotlin Multiplatform.
• Build backend services and APIs with Java/Kotlin and Spring Boot.
• Work with cloud services, CI/CD, monitoring and production support.
• Improve performance, reliability, security, and UX.
• Use AI coding tools to assist development, testing, documentation, and debugging.
• Collaborate with product, design, architecture, security and platform teams.
• Mentor other developers and promote good engineering practices.

Connaissances

Mobile development

Kotlin Multiplatform

iOS/Android architecture

Kotlin

Java/Spring Boot

CI/CD

Description du poste

N-iX is a global technology company that helps industry-leading companies and Fortune 500 firms build software products and scalable engineering solutions. Since 2002, we’ve become a team of 2,400+ tech professionals working across 40+ countries worldwide, now actively growing in LATAM. With our office in Medellín and a 100+ strong tech community in the region, we offer flexible work options, global collaboration, room to grow, and opportunities to contribute to meaningful global project

Currently, we are looking for a Senior Full Stack Mobile Developer to join our Clint`s team. The expert who can build modern mobile products end-to-end: from the mobile app experience to backend services, APIs, cloud services and production quality. This role is for someone who enjoys solving real product problems, writing clean code, learning new technologies and using AI tools to work faster and better.

You will join a team building next-generation digital financial products used by customers at scale. You will work across the mobile app, shared mobile logic, backend services and production systems.

What you will do:

• Build and improve mobile features used by real customers.
• Develop shared business logic for mobile platforms, mainly using Kotlin Multiplatform (KMP).
• Build backend services and APIs using Java/Kotlin and Spring Boot.
• Work with cloud services, CI/CD pipelines, monitoring and production support.
• Improve performance, reliability, security and user experience.
• Use AI coding tools to help with development, testing, documentation and troubleshooting.
• Work closely with product, design, architecture, security and platform teams.
• Help define good engineering practices and mentor other developers.

What we are looking for

• We are looking for a strong engineer, not just a person who knows one framework. KMP experience is a strong advantage, but it is not the only path into this role.
• Strong experience in mobile application development.
• Deep understanding of iOS & Android Architecture Components.
• Strong Kotlin skills and good understanding of modern mobile architecture.
• Experience building production-grade apps with good quality, performance and maintainability.
• Backend development experience with Java 7+ and Spring Boot.
• Understanding of APIs, microservices and event-driven systems.
• Experience with CI/CD, automated testing and production systems.
• Ability to take ownership of a feature from design to production.
• Good communication skills and ability to work with multiple teams.

Cross-platform experience

• Our strategic direction is Kotlin Multiplatform, because it lets us reuse business logic while still keeping native-quality mobile experiences. However, we also welcome candidates with strong experience in other cross-platform technologies.
• Kotlin Multiplatform (KMP) experience is preferred.
• Flutter experience is relevant, especially if you worked on architecture, shared logic and production apps.
• React Native experience is relevant, especially if you worked on platform integration and complex mobile products.
• If you are strong in Flutter or React Native and willing to learn KMP, we want to talk to you.

Backend and cloud experience

• Java 7+ and/or Kotlin backend development.
• Spring Boot and REST/API development.
• Microservices and distributed systems.
• Kafka or other event-based technologies.
• Cloud services, preferably AWS.
• High-scale or high-availability production systems.

AI-assisted development

• We believe modern software development combines strong engineering fundamentals with the effective use of AI and automation.
• As part of our engineering culture, we follow a Specification-Driven Development (SDD) approach, where clear requirements, technical designs, examples, and tests are used to drive implementation and ensure high-quality outcomes.
• Use AI coding assistants such as GitHub Copilot, Cursor, Claude Code, Gemini Code Assist or similar tools.
• Use AI to help with code generation, unit tests, documentation, refactoring and debugging.
• Critically review AI-generated output and maintain high standards for code quality, security, performance, and maintainability.
• Be open to working with AI agents as part of the development lifecycle.

Nice to have

• Experience in fintech, banking, payments or other regulated environments.
• Experience with Apple Pay, Google Pay or wallet/payment integrations.
• Experience building modular mobile apps or shared SDKs/libraries.
• Experience with observability, performance profiling and production incident analysis.

Who will succeed in this role?

• A developer who can learn fast and is not afraid of new technologies.
• Someone who understands both product experience and system design.
• A person who can work independently but also collaborate well with others.
• An engineer who cares about clean code, reliability, security and customers.
• Someone who wants to be part of the next generation of AI-empowered full stack development.

In simple terms: we are looking for a strong mobile-first full stack developer who can build customer-facing apps, connect them to strong backend services, learn KMP if needed, and use AI tools as part of a modern development workflow.

We offer*:

• Flexible working format - remote, office-based or flexible
• A competitive salary and good compensation package
• Personalized career growth
• Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more)
• Active tech communities with regular knowledge sharing
• Education reimbursement
• Memorable anniversary presents
• Corporate events and team buildings
• Other location-specific benefits

*not applicable for freelancers