Senior KMP Engineer in Warsaw

Location: Remote anywhere from Poland

Work mode: Remote

Type of cooperation: B2B contract

Salary range: B2B: 7000 - 7500 Euro/month - netto

About The Company/project

Build the Next Generation of Digital Financial Products. Join a team building one of the largest digital financial platforms in its market, serving millions of customers and processing millions of real-time financial transactions every month. This is a unique opportunity to work on products that have become a natural part of users' daily lives, delivering fast, secure, and seamless financial experiences at scale.

As a Senior KMP Engineer, you will contribute across the entire technology stack - from customer-facing mobile applications and shared cross-platform logic to backend services, APIs, cloud infrastructure, and large-scale production systems.

Our core technology stack includes Kotlin, Kotlin Multiplatform (KMP), Java, and Spring Boot.

Why Join Us?

• Build products used daily by millions of customers.
• Work on large-scale, business-critical systems processing millions of real-time financial transactions every month.
• Take full end-to-end ownership of features, from design and implementation to deployment and production support.
• Help shape the future of our mobile platform strategy through Kotlin Multiplatform (KMP).
• Collaborate in small, high-impact teams where engineers have real influence on technical decisions.
• Solve challenging problems across mobile development, backend services, cloud infrastructure, scalability, reliability, and security.
• Be part of an engineering culture where AI is used every day as a practical development tool, accelerating delivery and enabling engineers to focus on solving meaningful business and technical challenges.

Responsibilities

What You’ll Do

• Develop shared business logic across mobile platforms using Kotlin Multiplatform (KMP).
• Design and build backend services and APIs using Java, Kotlin, and Spring Boot.
• Build and enhance customer-facing mobile features used by real customers every day.
• Work with cloud services, CI/CD, observability, monitoring, and production systems.
• Improve scalability, reliability, performance, security, and user experience.
• Collaborate closely with product, design, architecture, security, and platform teams.
• Drive engineering excellence through technical leadership, mentoring and best practices.

You Are An Ideal Candidate If You Have What We're Looking For

• Strong commercial experience in mobile application development with Kotlin or Kotlin Multiplatform.
• Deep understanding of modern Android OR iOS architectures and software design principles.
• Strong Kotlin skills and experience building high-quality, production-grade applications.
• Some backend development experience with Java, Spring Boot, APIs, and microservices - Big Advantage.
• Familiarity with distributed systems, event-driven architectures, and modern engineering practices.
• Experience with CI/CD, automated testing, and production environments.
• Ability to take end-to-end ownership of features from design through production.
• Strong communication and collaboration skills.

Nice To Have

• Experience in fintech, banking, payments, or other regulated industries.
• Experience with Apple Pay, Google Pay, wallet technologies, or payment integrations.
• Experience building modular mobile applications, SDKs, or shared libraries.
• Experience with observability, performance optimization, and production incident analysis.