Mid-Senior Crypto Developer - Hybrid - Warsaw

Mid-Senior Crypto DeveloperLocation: Warsaw (Hybrid, a minimum of 1 day per week in the office)Contract type: B2BWe 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.