Kotlin Backend Engineer - Fintech Microservices

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

Benefits offered by this job

Great Place to Work

Centre of internal trainings

Profit sharing

Medical care

Open management team

Team events

Job summary

Sii Poland is hiring for a backend software engineer to join a fintech platform focused on expense management. You will design, build and maintain Kotlin-based microservices and collaborate with cross‑functional teams across Platform, Services, SMB and more.

You’ll support performance monitoring, reliability and scalability, participate in code reviews, and contribute to architecture improvements while working in a dynamic, English‑speaking environment in Poland.

Qualifications

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

Responsibilities

• Design, build, and maintain microservices using Kotlin.
• Collaborate with cross-functional teams to deliver solutions across Platform, Services, SMB, and other domains.
• Support system performance monitoring and contribute to reliability and scalability improvements.
• Participate in code reviews and maintain high code quality standards.
• Contribute to continuous improvement of code quality and system architecture.
• Troubleshoot and resolve technical issues.

Skills

Backend development

Kotlin proficiency

Cloud environments

Relational databases

Testing & observability

English

Tools

Kotlin

Microservices

AWS

Kubernetes

PostgreSQL

JUnit

Grafana

Job description

Sii Poland is hiring for a backend software engineer to join a fintech platform focused on expense management. You will design, build and maintain Kotlin-based microservices and collaborate with cross‑functional teams across Platform, Services, SMB and more.

You’ll support performance monitoring, reliability and scalability, participate in code reviews, and contribute to architecture improvements while working in a dynamic, English‑speaking environment in Poland.