Principal Backend Engineer (API, Java, Go, Rust)

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

Join a global engineering team building next‑generation payment processing capabilities as part of the organisation’s Future State Architecture programme.
This initiative focuses on creating a lean, reusable, and high‑performing payment engine that will underpin modern, scalable, and cost‑efficient transaction processing across the enterprise.

You will be part of a core team delivering backend and API‑driven solutions that prioritise speed, resilience, and quality—enabling new product features to be rolled out quickly and safely. Working in an inner‑sourcing model, you will collaborate globally to leverage existing software assets, enhance shared components, and drive the migration to cloud‑based infrastructure.

Sounds like your kind of challenge?

What you'll be doing

Deliver enterprise‑grade payment processing software, establishing technical standards and ensuring engineering excellence.
Build and maintain scalable microservices and API layers using Java (primary) and Go / Rust (advantage).
Deliver high‑quality code artefacts with comprehensive test coverage, ensuring quality gates are met or exceeded.
Design for high availability, resilience, and performance, implementing best practices in distributed system architecture.
Modernise existing payment components for cloud‑native environments, guiding transformation and migration strategies.
Lead by example—set technical direction and development standards for global teams.
Provide expert advice on both technical and business issues, influencing design decisions and system roadmaps.
Partner with architecture, DevOps, and security teams to align design, CI/CD, and infrastructure automation pipelines.
Analyse and resolve architectural blockers, ensuring that delivery progresses according to roadmap objectives.
Evaluate vendor technologies, define implementation standards, and develop cost‑effective technical strategies.
Act as a subject‑matter expert in APIs and Payments within the programme.
Provide mentoring and coaching for engineers, promoting an engineering culture based on responsibility, experimentation, and continuous learning.
Work closely with cross‑functional teams to ensure DevSecOps best practices, automated testing, and observability are embedded.

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

What you get in return

Hybrid work setup – two days a week from the office
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

15 + years of overall technology experience, including 10+ years in backend and microservices engineering.
Strong background in API architecture, design, and development, including documentation, gap analysis, and data modelling.
Expertise in Java (Spring Boot); additional experience in Go or Rust is beneficial.
Advanced understanding of distributed system design, JVM tuning, and performance diagnostics.
Hands‑on knowledge of containerisation (Docker, Kubernetes) and service meshes.
In‑depth experience with Kafka (event streaming platforms) – cluster setup, configuration, producer/consumer development.
Familiar with CI/CD, DevOps, and cloud delivery (AWS / Azure / Private Cloud), including network, firewall and IAM concepts.
Expertise in observability and monitoring (Splunk, Grafana, Prometheus, Jaeger, Kiali, Open Telemetry).
Strong SQL skills and understanding of distributed databases.
Degree in Computer Science, Engineering or related field.
Excellent communication, problem‑solving, and stakeholder engagement skills in English.

Preferred Experience:

Background in financial applications, especially payments and core banking systems.
Proven ability to design technical solutions within large global organisations.
Experience mentoring and leading teams of engineers across geographically distributed locations.
Keen interest in modern development practices: API‑first architecture, DevSecOps, Cloud‑native engineering, and Inner Sourcing.

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.

Ready to take the next step?

Submit your application! We look forward to reviewing your profile 😊

Know someone who might be a great fit?
Feel free to share this opportunity using the referral link: Mindbox Referrals System