December 17, 2025

Android Kotlin Developer – banking sector project

Senior • Hybrid

Warsaw, Poland

Sii ensures that all employment-related decisions are made solely on the basis of qualifications and competencies. We are committed to equal treatment of all individuals, regardless of any protected characteristics, and promoting a diverse and inclusive work environment.


Join a team working on a comprehensive rebuild of a mobile application for one of the leading banks in Poland. You will actively contribute to the development of modern solutions used by hundreds of thousands of customers.

In this role, you will influence the application’s architecture, code quality, and feature development direction. Collaboration with product teams and IT departments will take place in a dynamic, agile environment.


Your tasks

  • Participate in a large-scale mobile application rebuild project within the banking sector

  • Develop and implement new features for the Android platform using Kotlin

  • Provide technical support to the team, including troubleshooting, code review, and mentoring

  • Ensure high code quality and contribute to architectural decisions

  • Collaborate closely with project teams, product owners, and other IT units


Requirements

  • Minimum 5 years of experience in programming for the Android platform

  • Very good knowledge of Android SDK, Kotlin, and Java SDK, as well as experience with Jetpack Compose

  • Understanding of system integration concepts: REST, JSON, SOAP web services, XML, XSD

  • Experience with code review (e.g., GIT, Gerrit) and refactoring is a plus; familiarity with Clean Code principles

  • Good command of English (minimum communicative level, spoken and written)

  • Willingness to work in a hybrid model with 1–2 days per week from the office in Warsaw

  • Fluent Polish required

  • Residing in Poland required


What we offer 

  • Great Place to Work since 2015 - it’s thanks to feedback from our workers that we get this special title and constantly implement new ideas 

  • Employment stability - revenue of PLN 2.1BN, no debts, since 2006 on the market 

  • We share the profit with Workers - over PLN 76M has already been allocated for this aim since 2022 

  • Attractive benefits package - private healthcare, benefits cafeteria platform, car discounts and more 

  • Comfortable workplace – class A offices or remote work 

  • Dozens of fascinating projects for prestigious brands from all over the world 

  • PLN 1 000 000 per year for your ideas - with this amount, we support the passions and voluntary actions of our workers 

  • Investment in your growth – meetups, webinars, training platform and technology blog – you choose 

  • Fantastic atmosphere created by all Sii Power People 


Join the Sii team – develop your skills, gain experience, and build your career!