Job title: Senior Fullstack Mobile Engineer (KMP/Java)
Location: Remote anywhere from Poland
Work mode: Remote
Type of cooperation: B2B contract
Salary range: B2B: 7000 - 7500 Euro/month - netto
Senior Fullstack Mobile Engineer (KMP/Java)
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
We are looking for strong engineers who enjoy solving product and technical challenges across multiple layers of the technology stack.
- 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
- 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.