Kotlin Backend Engineer – Fintech Microservices Trailblazer

Sii Poland; Białystok; On-site; PLN 150,000 - 210,000; Full time

Benefits offered by this job

Great Place to Work

Centre of internal trainings

Profit sharing

Medical care

Open and accessible management team

Job summary

Sii Poland is seeking a skilled Backend Kotlin Developer to join a fintech platform enhancing company expense management. You will design and maintain microservices, collaborate with Platform, Services, and SMB teams, and contribute to performance monitoring and reliability improvements.

The role requires 3+ years in software development, Kotlin in commercial projects, backend and microservices experience, and familiarity with AWS/Kubernetes, PostgreSQL, JUnit, and Grafana.

Qualifications

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

Backend development

Microservices architecture

Cloud environments

Relational databases

Testing & observability

English

Tools

PostgreSQL

JUnit

Grafana

AWS

Kubernetes

Job description

Sii Poland is seeking a skilled Backend Kotlin Developer to join a fintech platform enhancing company expense management. You will design and maintain microservices, collaborate with Platform, Services, and SMB teams, and contribute to performance monitoring and reliability improvements.

The role requires 3+ years in software development, Kotlin in commercial projects, backend and microservices experience, and familiarity with AWS/Kubernetes, PostgreSQL, JUnit, and Grafana.