Kotlin Backend Engineer – Fintech Microservices

Sii Poland; Piła; On-site; PLN 140,000 - 210,000; Full time

Benefits offered by this job

Great Place to Work

Solid financial situation

Contracts with the biggest brands

Centre of internal trainings

Many experts you can learn from

Open and accessible management team

Profit sharing

Passion Sponsorship program

Regular integration events and trips

Comfortable and well-equipped offices

MySii app

Medical care

Job summary

Sii Poland is seeking a skilled backend software engineer to join our fintech platform team in Poland. You will design, build, and maintain Kotlin-based microservices, collaborating with Platform, Services, SMB, and other domains to deliver robust financial solutions.

The role focuses on scalable backend systems, cloud exposure (AWS, Kubernetes), PostgreSQL, testing with JUnit, and observability with Grafana. Fluent English required; Polish residence is expected.

Qualifications

• 3+ years of professional software development experience.
• Hands-on Kotlin in commercial projects.
• Experience building backend systems and working 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.
• 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

Backend development

Microservices

AWS

Kubernetes

PostgreSQL

JUnit

Grafana

English

Tools

PostgreSQL

JUnit

Grafana

Job description

Sii Poland is seeking a skilled backend software engineer to join our fintech platform team in Poland. You will design, build, and maintain Kotlin-based microservices, collaborating with Platform, Services, SMB, and other domains to deliver robust financial solutions.

The role focuses on scalable backend systems, cloud exposure (AWS, Kubernetes), PostgreSQL, testing with JUnit, and observability with Grafana. Fluent English required; Polish residence is expected.