Role Description
We are looking for a Senior Software Engineer to join a high-caliber Web3 engineering team of our client. This is a deeply technical, hands-on individual contributor role. The successful candidate will own the delivery of core backend services supporting wallet operations, asset transfers, transaction orchestration, blockchain integrations, and event-driven workflows operating at scale within regulated financial environments.
• Implement and operationalize core backend services with fault tolerance, security, and scalability.
• Build API-first services integrating blockchain networks, third-party provider solutions, and internal systems with strong consistency guarantees.
• Implement secure service communications using cryptographic signatures, key management, and zero-trust architecture principles.
• Operationalize event-driven systems using Apache Kafka and asynchronous messaging patterns.
• Build highly available, strongly consistent, horizontally scalable services.
• Implement robust concurrent and asynchronous processing patterns for multi-threaded workloads.
• Integrate Web3 SDKs and libraries for on-chain interactions, transaction signing, and state monitoring.
• Implement structured logging, distributed tracing, metrics, and OpenTelemetry instrumentation.
• Produce and maintain high test coverage via automated unit, integration, and functional testing frameworks within CI/CD pipelines.
• Produce and maintain technical documentation, API specifications, and operational runbooks.
Qualifications
• 7 or more years of software engineering experience building and operating production-grade backend systems in regulated financial or enterprise environments.
• Experience with blockchain networks, smart contracts, consensus mechanisms, crypto integration, or tokenization platforms.
• Extensive hands-on proficiency in Java and Spring Boot.
• Comfort operating across polyglot stacks.
• Deep expertise in API-first design, RESTful service contracts, and microservices architecture patterns.
• Strong command of concurrent, multi-threaded, and asynchronous programming models.
• Proven track record delivering highly available, strongly consistent, and distributed applications.
• Hands-on experience building event-driven solutions using Apache Kafka.
• Strong understanding of CI/CD, DevSecOps practices, secure SDLC, and automated security controls.
• Hands-on experience with OpenTelemetry, distributed tracing, and observability platforms.
• Strong technical writing skills; demonstrated ability to produce API specs and runbooks.
• Proven experience using Web3 libraries and SDKs (Web3.js, Ethers.js, or equivalent).
Requirements
• Extensive hands-on proficiency in TypeScript, Node.js, and/or NestJS.
• Direct experience with Ethereum, Bitcoin, Solana, XRPL, and other distributed ledger technologies.
• Familiarity with MPC (Multi-Party Computation), HSMs, and enterprise key management systems.
• Experience implementing Zero Trust security architecture end-to-end.
• Knowledge of tokenization, stablecoins, settlement systems, and digital asset operations.
• Contributions to open-source blockchain projects or Web3 tooling.
Benefits
• International experience in a stable company: the company has offices in Antwerp, Leuven, Lisbon, Krakow, Kyiv, New York and operates on the market for over 15 years.
• Passionate team in an innovative casual, positive, and open work environment ready to meet your new ideas.
• Great opportunities for personal and professional development as well as the chance to change the way the business works in the financial world.