Principal Backend Engineer

At Mindbox we connect top IT talents with technology projects for leading enterprises across Europe.

We are looking for a Senior API Engineer / Technical Lead to provide engineering expertise for our Future State Architecture. You will play a key role in designing and developing best-in-class payment processing solutions, ensuring scalability, resilience, and compliance with global standards. This role involves technical leadership, architecture guidance, and hands-on development in a highly collaborative environment.

Sounds like your kind of challenge?

What you’ll be doing

Deliver engineering expertise for Future State Architecture, producing best-in-class payment processing capabilities.
Create high-quality artefacts that set the standard for the team, ensuring quality gates and robust test scripts.
Design, code, test, debug, and document programs as required.
Provide architecture guidance to developers based on best practices and global standards.
Lead and mentor team members, fostering technical excellence and innovation.
Partner with DevOps teams to enable automated infrastructure delivery and CI/CD pipelines.
Resolve architectural and development blockers, ensuring timely delivery.
Conduct feasibility studies, cost/benefit analyses, and prepare technical specifications.
Ensure compliance with all relevant controls and standards.
Stay up-to-date with emerging tools, technologies, and cybersecurity regulations.

Note: Detailed project information will be shared during the recruitment process.

What you get in return

Flexible cooperation model – choose the form that suits you best
(B2B, employment contract, etc.)
Hybrid work setup – 3 days / week from office in Kraków
Collaborative team culture – work alongside experienced professionals eager to share knowledge
Continuous development – access to training platforms and growth opportunities
Comprehensive benefits – including Interpolska Health Care, Multisport card, Warta Insurance, and more
High quality equipment – laptop and essential software provided

Who we’re looking for

Bachelor’s degree in Computer Science, Engineering, or related field.
15+ years of applied experience as an API engineer.
Strong expertise in API design, architectural artefacts, and low-level designs.
10+ years of engineering experience in back-end microservices, application security, and middleware.
Proficiency in Java (Go and Rust are a plus), JVM tuning, and performance optimization.
Expertise in microservices, Spring Boot, Docker, Kubernetes, service mesh.
Experience with Kafka, cluster configuration, and data streaming.
Knowledge of monitoring tools (Splunk, Grafana, Prometheus) and DevOps practices.
Familiarity with cloud environments, VPC, identity and access management, and Linux-based infrastructure.
Strong SQL and distributed database knowledge.
Experience in financial services or payment systems is an advantage.
Excellent leadership, mentoring, and communication skills.
Ability to work independently, manage priorities, and thrive in a dynamic environment.

Joining this project you’ll become part of Mindbox – a tech-driven company where consulting, engineering, and talent meet to build meaningful digital solutions. We’ll back you up every step of the way, accelerate your development, and ensure your skills make a difference.

Principal Backend Engineer

Kraków

B2B

1600 - 1800 PLN/md +VAT

Apply for position

I will handle your recruitment

Karolina Cieślik

SUPPORT & BENEFITS

Private healthcare

Fast access to doctors and medical tests.

Mindbox fully covers the individual package. You can extend the coverage to your partner and family on preferential terms. A wide network of medical providers and clear rules for everyday use.

Multisport

Energy that pays off.

We cover 50% of the card cost. You get access to thousands of sports facilities across Poland, plus a convenient mobile app. Additional cards for family members are available.

Training & development

Practical support for your career growth.

We co‑fund courses, certifications and conferences under a clear Training Policy. You also get access to a library of recorded webinars and trainings – available whenever you need them.

Eyewear or contact lenses co‑funding

Clear vision means comfortable work.

Up to PLN 500 every two years, with an additional PLN 300 available in justified cases. Simple reimbursement, regardless of your form of cooperation.

Group life insurance

Real protection from day one.

Option I is fully funded by Mindbox, Option II is co‑funded. You can include your partner and adult children, with coverage that also applies to treatment and hospitalisation abroad.

Ongoing support from the Talent Network Development

You’re not on your own in a project.

Regular contact, quick response and a partnership‑based approach. You focus on your work — we help take care of the rest.

Regular integration meet‑ups

Relationships that work beyond the project.

Cyclical meet‑ups for contractors in major cities across Poland. A space to talk, exchange experience and stay in real contact with the Mindbox team.

Annual company‑wide integration

One event. The whole community.

A two‑day company gathering with accommodation, transport and a full activity programme. Time to connect teams from across Poland and build shared experiences.