Backend Product Engineer (Payments / Kotlin)

DNA Technology; Remote; PLN 180,000 - 240,000; Full time

Job summary

A leading technology firm is seeking a Backend Product Engineer to enhance payment processing systems crucial for business growth. In this role, you will develop backend features and work with various teams. Strong experience in Kotlin or Java and a solid understanding of relational databases are required. The role offers a fully remote option, emphasizing individual growth and clear communication within the team. Applications are welcomed for those looking for impactful work in a supportive environment.

Benefits

Individual growth sessions

Transparent communication

Influence on operational decisions

Qualifications

• Strong backend experience with Kotlin or Java (4+ years), including building and maintaining production systems.
• Ability to work independently with incomplete requirements, asking the right questions.
• Strong sense of ownership and responsibility for production outcomes.

Responsibilities

• Build backend features end-to-end from business clarification to production.
• Work on real payment flows with direct business implications.
• Develop, integrate, and improve existing systems.

Skills

Kotlin or Java

Relational databases

Event-driven architectures

Tools

AWS

PostgreSQL

Kafka

Spring WebFlux

Job description

As a Backend Product Engineer, you will work on one of the most critical parts of our business — payment processing systems.

This is a highly business-oriented role. Payments are at the core of the company’s growth, and the stability, correctness, and scalability of this system have a direct impact on business results.

Rate: 150–180 PLN + VAT (B2B) per hour.

Location: Fully remote (Poland)🌎 or Łódź (Poland)

Tech stack: Kotlin / Java, PostgreSQL, Kafka, AWS

Your everyday playground:

• Building backend features end-to-end — from clarifying business needs, through implementation and testing, to production.
• Working on real payment flows that are used every day and have a direct business impact.
• Cooperating with Product, other teams, and external partners to shape solutions together.
• Taking responsibility for the quality and stability of systems running in production.
• Developing, integrating, and improving existing systems.
• Reviewing code and supporting teammates as part of a collaborative team.
• Working with technical and business documentation and turning it into working solutions.
• Running functional and manual tests of different card payment scenarios, including certification-related checks.

* The role combines software development and domain-focused work — roughly 50% development and 50% documentation, testing, and certification-related activities.

What are we looking for? 🕵️♀️

• Strong backend experience with Kotlin or Java (4+ years), including building and maintaining production systems.
• Solid understanding of relational databases and asynchronous, event-driven architectures.
• Ability to work independently with incomplete and evolving requirements, asking the right questions along the way.
• Strong sense of ownership and responsibility for what goes to production.
• Hands-on, critical mindset — you think through problems and solutions, not just implement tickets.

Bonus points:

• Experience with payment, fintech, or other regulated systems.
• Familiarity with PCI DSS–compliant environments or end-to-end certification processes (e.g. EMV L3).
• Knowledge of Spring WebFlux and Kotlin Coroutines.

Why join us? 🌟

• At DNA Technology, we believe in clear communication - we regularly talk about what works and what doesn’t, and how we can make things better (not just in code).
• Your development is extremely important to us! You can count on individual growth sessions to support you on your unique professional journey.
• We don’t do layers of management. Everyone has a voice and real influence on how we work.

Sounds like a fit? Let’s talk! 🚀