Fintech Kotlin Backend Engineer — Microservices

Sii Poland; Łódź; On-site; PLN 180,000 - 300,000; 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 hiring a backend Kotlin developer to join a fintech platform focused on expense management and integration with partner systems. You will design, build, and maintain microservices within a finance-driven backend, contributing to performance, reliability, and scalable architecture from our Łódź office.

Ideal candidates have 3+ years in software development, strong Kotlin skills, experience with microservices, cloud basics, PostgreSQL, and testing/observability tools.

Qualifications

• Minimum 3 years of professional software development experience.
• 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 (PostgreSQL) and testing/observability tools (JUnit, Grafana).
• Good command of English; residing in Poland is 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 reliability and scalability improvements.
• Participating in code reviews and maintaining high code quality standards.
• Contributing to continuous improvement of code quality and system architecture.
• Troubleshooting and resolving technical issues.

Skills

Kotlin

Backend

Microservices

Cloud AWS

Kubernetes

PostgreSQL

JUnit

Grafana

English

Tools

JUnit

Grafana

Job description

Sii Poland is hiring a backend Kotlin developer to join a fintech platform focused on expense management and integration with partner systems. You will design, build, and maintain microservices within a finance-driven backend, contributing to performance, reliability, and scalable architecture from our Łódź office.

Ideal candidates have 3+ years in software development, strong Kotlin skills, experience with microservices, cloud basics, PostgreSQL, and testing/observability tools.