Kotlin Backend Engineer for Fintech Microservices

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

Benefits offered by this job

Centre of internal trainings

Profit sharing

Medical care

Regular integration events and trips

Great Place to Work

Job summary

Sii Poland is seeking a backend engineer to join a fintech platform that streamlines company expense management. The role focuses on designing, building and maintaining Kotlin-based microservices integrated into partner systems and cloud environments.

You will collaborate with cross‑functional teams across multiple domains, contribute to performance monitoring, reliability and scalability, and participate in code reviews to uphold high quality standards.

Qualifications

• Minimum 3 years of professional software development experience.
• Hands-on Kotlin experience in commercial projects.
• Experience building backend systems and microservices architecture.
• Basic experience with cloud environments (e.g., AWS, Kubernetes).
• Experience with relational databases (e.g., PostgreSQL) as well as testing and 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 systems

Cloud (AWS/Kubernetes)

PostgreSQL

Testing & observability (JUnit, Graf S

English

Tools

Kubernetes

Job description

Sii Poland is seeking a backend engineer to join a fintech platform that streamlines company expense management. The role focuses on designing, building and maintaining Kotlin-based microservices integrated into partner systems and cloud environments.

You will collaborate with cross‑functional teams across multiple domains, contribute to performance monitoring, reliability and scalability, and participate in code reviews to uphold high quality standards.