Senior KMP Engineer (Mobile & Backend)

About the 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.

This is how we organize our work

This is how we work

• at the client's site

Your responsibilities

• 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.

Our requirements

• 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.

Optional

• 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.

This is how we work on a project

• Clean Code

Development opportunities we offer

• conferences in Poland
• development budget
• support of IT events
• technical knowledge exchange within the company

Benefits

• sharing the costs of sports activities
• private medical care
• sharing the costs of foreign language classes
• fruits
• integration events
• corporate gym
• coffee / tea
• drinks
• birthday celebration
• employee referral program

Recruitment stages

• Rozmowa telefoniczna – wstępna rozmowa z Rekruterem
• Rozmowa kwalifikacyjna – spotkanie z przedstawicielem firmy

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.

Integral Solutions

Integral Solutions, Informatica Platinum Partner Enterprise, od ponad 20 lat dostarcza nowoczesne rozwiązania IT dla biznesu, oferując usługi m.in. w zakresie integracji danych, Data Engineering (Big Data) oraz Data Governance. Specjalizując się w rekrutacji pracowników z branży IT, nie tylko w obszarze danych, pomaga Klientom powiększać zespoły projektowe o profesjonalistów IT.