Fullstack Mobile Developer ( Kotlin)

Integral Solutions - Data & AI; Województwo mazowieckie; Remote; PLN 317,000 - 366,000; Full time

Job summary

Integral Solutions - Data & AI is seeking a Kotlin Multiplatform Developer to join a remote-first team building a leading digital payments platform. You will develop shared mobile logic using Kotlin Multiplatform and contribute to backend services with Java/Kotlin and Spring Boot, while embracing modern tooling and AI-assisted development.

This B2B role from Poland offers flexible remote collaboration, hands-on ownership of features from design to production, and work with cloud services, CI/CD

Qualifications

• Experience with Kotlin Multiplatform (KMM/KMP) required.
• Backend development with Java and Spring Boot is a strong plus.
• Strong knowledge of mobile architecture and API design.
• Ability to own features end-to-end in a fast-paced environment.

Responsibilities

• Develop shared mobile logic for Kotlin Multiplatform and contribute to backend services.
• Build and improve mobile features used by real customers.
• Develop backend services and APIs using Java/Kotlin and Spring Boot.
• Work with cloud services, CI/CD pipelines, monitoring and production support.
• Use AI coding tools to assist development, testing, and documentation.
• Collaborate with product, design, architecture, security and platform teams.
• Improve performance, reliability, security and user experience.

Skills

Kotlin Multiplatform

KMM/KMP

Java

Spring Boot

CI/CD

APIs

Microservices

Event-driven

Android Architecture

iOS Architecture

Production-grade apps

Testing

Tools

Kafka

Job description

Job title: Kotlin Multiplatform Developer

Location: Remote anywhere from Poland

Work mode: Remote

Type of cooperation: B2B contract

Salary range: B2B 6500 - 7500 Euro/month- neto

About The Company/project

Join the team behind one of the most widely adopted digital payment and financial platforms in its market, used daily by millions of people to send money instantly, make seamless digital payments, and manage essential financial activities.

This mobile-first product has become a key part of users' everyday lives, delivering fast, secure, and intuitive financial experiences at massive scale.

Powered by a highly available distributed architecture and real-time transaction processing, the platform handles millions of interactions every month while maintaining exceptional standards of performance, reliability, and security.

As part of the team, you will contribute to a product that combines cutting-edge technology with tangible impact, shaping how millions of users interact with modern financial services every day.

Responsibilities

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

You Are An Ideal Candidate If You Have

We are looking for a strong engineer, not just a person who knows one framework.

Experience with modern Kotlin Multiplatform technologies (KMM/KMP) is highly valued, but candidates with other strong mobile or backend experience are also encouraged to apply.

• Experience working with modern software development technologies is important, with Kotlin Multiplatform (KMP) being a strong advantage.
• Some backend development experience with Java and Spring Boot. will be huge advantage
• 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.
• 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

W are using 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.

Nice To Have

• Experience with Kafka or other message broker / queue management tools.
• Strong communication and teamwork skills
• Ability to thrive in a fast-paced, dynamic environment
• Proactive, "Can-Do" attitude
• Strong problem-solving and system-thinking abilities