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Job
· Senior
Senior Software Engineer (Java)
Software Engineer
• Senior
• Remote
• Full-time
•
Portugal
A deeply technical, hands-on individual contributor role on a Web3 engineering team, owning core backend services for wallet operations, asset transfers, transaction orchestration and blockchain integrations in regulated financial environments.
Responsibilities
- ▹Implement and operationalize core backend services with fault tolerance, security and scalability
- ▹Build API-first services integrating blockchain networks, third-party 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 in CI/CD pipelines
- ▹Produce and maintain technical documentation, API specifications and operational runbooks
Requirements
- ▹7+ years of software engineering experience building and operating production-grade backend systems in regulated financial or enterprise environments
- ▹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
- ▹Strong command of concurrent, multi-threaded and asynchronous programming models
- ▹Proven track record delivering highly available, strongly consistent, distributed applications
- ▹Hands-on experience building event-driven solutions using Apache Kafka
- ▹Solid understanding of messaging patterns including pub/sub, event sourcing and saga/choreography orchestration
- ▹Strong understanding of CI/CD, DevSecOps practices and secure SDLC
- ▹Hands-on experience with OpenTelemetry and distributed tracing
- ▹Strong technical writing skills for API specs and runbooks
Nice to have
- ▹Extensive hands-on proficiency in TypeScript, Node.js and/or NestJS
- ▹Direct experience with Ethereum, Bitcoin, Solana, XRPL and other distributed ledger technologies
Soft skills
Strong technical writing communicationIndependent, deeply technical individual contributor mindset
About the company
IntellectEU is an international technology company focused on digital finance and emerging technologies, with two decades of expertise in payments, blockchain and capital markets.
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