Kotlin Backend Engineer – Fintech Microservices & Cloud

Sii Poland; Bydgoszcz; On-site; PLN 180,000 - 240,000; Full time

Benefits offered by this job

Centre of internal trainings

Profit sharing

Regular integration events and trips

Medical care

Job summary

Sii Poland is hiring for a backend-focused role working on a modern fintech platform that supports company expense management. You will design, build, and maintain Kotlin-based microservices and collaborate with cross-functional teams across Platform, Services, SMB, and more.

The position emphasizes reliability, scalability, and code quality, with opportunities to contribute to system architecture and performance improvements.

Qualifications

• Minimum 3 years of professional experience in software development.
• Hands-on experience with Kotlin in commercial projects.
• Experience building backend systems and with microservices architecture.
• Basic experience with cloud environments (e.g., AWS, Kubernetes).
• Experience with relational databases (e.g., PostgreSQL) and testing/observability tools (e.g., JUnit, Grafana).
• Good command of English; residing in Poland required.

Responsibilities

• Designing, building, and maintaining microservices using Kotlin.
• Collaborating with cross-functional teams to deliver solutions across Platform, Services, SMB, and other domains.
• Supporting system performance monitoring and contributing to improvements in reliability and scalability.
• Participating in code reviews and maintaining high code quality standards.
• Contributing to the continuous improvement of code quality and system architecture.
• Troubleshooting and resolving technical issues.

Skills

Kotlin

Microservices

Backend

PostgreSQL

Testing

Observability

English

Tools

AWS

Kubernetes

JUnit

Grafana

Job description

Sii Poland is hiring for a backend-focused role working on a modern fintech platform that supports company expense management. You will design, build, and maintain Kotlin-based microservices and collaborate with cross-functional teams across Platform, Services, SMB, and more.

The position emphasizes reliability, scalability, and code quality, with opportunities to contribute to system architecture and performance improvements.