Kotlin Backend Engineer for Fintech Microservices

Sii Poland; Toruń; On-site; PLN 180,000 - 240,000; 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 for expense management. You will design, build, and maintain microservices using Kotlin, collaborating with cross-functional teams across Platform, Services, and SMB domains.

You will help improve reliability and scalability, participate in code reviews, and troubleshoot issues while keeping high code quality and architectural standards.

Qualifications

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

Responsibilities

• Design, build, and maintain microservices using Kotlin.
• Collaborate with cross-functional teams across Platform, Services, SMB, and other domains.
• Support system performance monitoring and 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

Microservices

Backend development

Cloud environments

Relational databases

English proficiency

Tools

PostgreSQL

JUnit

Grafana

Job description

Sii Poland is seeking a backend developer to join a modern fintech platform for expense management. You will design, build, and maintain microservices using Kotlin, collaborating with cross-functional teams across Platform, Services, and SMB domains.

You will help improve reliability and scalability, participate in code reviews, and troubleshoot issues while keeping high code quality and architectural standards.