Mid-Senior Crypto Developer - Hybrid - Warsaw

Mid-Senior Crypto Developer
Location: Warsaw (Hybrid, a minimum of 1 day per week in the office)
Contract type: B2B

We are currently recruiting for an exceptional business that is widely recognised as one of the premier employers to work for in Poland. They have earned a brilliant reputation in the local market for their inclusive workspace culture, highly advanced engineering standards, and top-tier technical challenges.

They are looking to expand their engineering team with a seasoned developer to focus on enterprise-grade cryptocurrency, blockchain networks, and digital transaction systems. This position bridges traditional high-performance backend engineering with advanced work across distributed ledgers, decentralised protocols, and secure transaction architectures.

What you will actually be doing:

• Leading the architectural design and rollout of production-grade cryptocurrency platforms and blockchain services.

• Constructing robust distributed systems, highly efficient API layers, and orchestration frameworks.

• Building and managing critical third-party integrations and ecosystem connections.

• Owning the software delivery lifecycle end-to-end, from conceptual system design to live production monitoring and scaling.

• Engineering core backend systems using Java whilst aligning seamlessly with frontend teams working in Angular.

• Safeguarding system integrity through stringent security protocols, comprehensive observability, and high availability.

• Establishing modern CI/CD automation, testing frameworks, and strict quality gates.

• Tackling complex system bottlenecks to continuously optimise performance and infrastructure scalability.

• Tracking global advancements across decentralised finance (DeFi), fintech, and ledger technology to keep platforms current.

What they need from you:

• At least 9-12 years of professional software engineering experience alongside a Bachelor's degree, OR 8+ years of relevant specialised experience paired with an advanced degree (Master's, MBA, or equivalent).

• A proven track record of delivering resilient, high-throughput distributed architectures.

• Deep practical knowledge of building microservices, custom APIs, and external platform integrations.

• Strong familiarity with proactive infrastructure monitoring, diagnostic alerting, and fault-tolerant setups.

• Total comfort operating within a Secure SDLC environment, including robust version control, automated deployments, and load testing.

• Comprehensive understanding of public and permissioned blockchain networks, DeFi patterns, and cryptographic security.

• Familiarity with private-key management, secure custody solutions, and distributed data ledgers.

• Direct exposure to major networks like Bitcoin, Ethereum, or Hyperledger frameworks.

• Fluent understanding of Solidity, EVM mechanics, and low-level Assembly coding.

• Prior experience in banking, fintech, or payment processing, with a solid grasp of transaction flows and compliance standards.

• Natural communication skills with the capability to facilitate technical discussions and guide project goals.

Highly Preferred:

• Solid domain expertise in financial technology, digital payments, or crypto ecosystems.

• Professional hands-on backend capability with Java combined with frontend familiarity in Angular (full-stack versatility is highly valued).

Please apply with an updated CV if you are interested in discussing this opportunity further.