Kotlin Backend Engineer for Fintech Microservices

Sii Poland; Lublin; On-site; PLN 201,000 - 312,000; 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 backend developer to join a modern fintech platform focused on expense management. You will design, build, and maintain Kotlin-based microservices and collaborate across multiple domains including Platform, Services and SMB. The role emphasizes reliability, scalability, and code quality within a dynamic team.

Responsibilities include performance monitoring, code reviews, and architectural improvements. English proficiency is required, and residence in Poland is mandatory.

Qualifications

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

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 improvements in reliability and scalability.
• 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

Kotlin

Backend

Microservices

Cloud

PostgreSQL

Testing & Observability

English

Poland resident

Tools

AWS

Kubernetes

Job description

Sii Poland is seeking a backend developer to join a modern fintech platform focused on expense management. You will design, build, and maintain Kotlin-based microservices and collaborate across multiple domains including Platform, Services and SMB. The role emphasizes reliability, scalability, and code quality within a dynamic team.

Responsibilities include performance monitoring, code reviews, and architectural improvements. English proficiency is required, and residence in Poland is mandatory.