Senior Full Stack Mobile Developer

N-iX; Polska; Remote; PLN 180,000 - 280,000; Full time

Benefits offered by this job

Flexible working format

Competitive salary

Career growth

Education reimbursement

Mentorship program

Tech talks and trainings

Active tech communities

Corporate events

Job summary

N-iX is seeking a mobile-first full stack developer to build customer-facing apps and connect them to robust backend services. You will learn Kotlin Multiplatform if needed and leverage AI tools as part of a modern development workflow.

The role emphasizes ownership, collaboration with product and architecture teams, and delivering high-quality, scalable software across platforms. Flexible remote options are available.

Qualifications

• Strong experience in mobile application development.
• Deep understanding of iOS & Android Architecture Components.
• Strong Kotlin skills and modern mobile architecture knowledge.
• Production-grade apps with performance and maintainability.
• Backend experience with Java 7+ and Spring Boot.
• Experience with APIs, microservices and event-driven systems.
• CI/CD, automated testing and production systems.
• Ownership of features from design to production.
• Good communication and cross-team collaboration.

Responsibilities

• Build and improve mobile features used by real customers.
• Develop shared business logic for mobile platforms, mainly Kotlin Multiplatform.
• 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 and documentation.
• Collaborate with product, design, security and platform teams.
• Mentor other developers and help define engineering practices.

Skills

Mobile development

Kotlin

Kotlin Multiplatform

Java/Spring Boot

CI/CD

REST APIs

Cloud AWS

AI-assisted development

Team collaboration

Tools

Kotlin/Java tooling

Spring Boot

AWS

GitHub Copilot

KMP tooling

Job description

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

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, centres 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