Senior Java Engineer (Krakow)

🎰 Senior Java Engineer: Build the Wallet Behind Millions of Players

Adaptiq × a major online gaming operator

The challenge:

Picture a platform where millions of players hit "play" at the same moment, every action moves real money, and the answer must come back in under a second. Now picture building it from scratch.

That's the PAM (Player Account Management) platform: real-time financial transactions, strict regulation, zero tolerance for lost cents, and traffic spikes that would make most systems sweat. No legacy code to inherit. Just a blank page and hard problems.

Your role:

You'll design and build the core backend of the platform and own your features end-to-end: from RFC to production monitoring. You'll work side by side with Principal Engineers, with real autonomy and real influence on the architecture.

What you'll do:

• Build services in Java 17+ / Spring Boot for wallets, ledger, payments, bonuses, and account state
• Create REST APIs and Kafka-based event flows for frontends, ops tools, and partners
• Make correctness non-negotiable: idempotency, clear transaction boundaries, failure handling, solid testing
• Bake in compliance: KYC/AML, responsible gaming, audit trails
• Keep production healthy with metrics, tracing, alerts, and on-call
• Shape the platform through RFCs and code reviews, and mentor teammates
• Work with AI-assisted tools daily

• Help migrate live from the existing third-party platform (parity testing, data validation, cutover)

   

What you bring:

• 5+ years in backend engineering, with strong Java 17+ and Spring Boot
• Experience with high-integrity transactional systems: payments, wallets, billing, banking, e-commerce, or gaming
• Deep PostgreSQL (or similar) knowledge: schema design, ACID, locking, tuning
• Event-driven architecture experience (Kafka, RabbitMQ), including idempotency and retries
• Automated testing as a habit: unit, integration, contract
• Hands-on production experience with containers, CI/CD, observability, and incident troubleshooting
• Solid grasp of multi-threading and fault-tolerant design

• Good English and comfort working across time zones

   

Bonus points:

✦ iGaming, betting, or fintech background
✦ Kubernetes and AWS (VPC, IAM, EKS, auto-scaling)
✦ Compliance-driven development experience
✦ Agentic development workflows
 

If you want your code to handle real money, real scale, and real responsibility, let's talk.