Blockchain Developer (Java)

IntellectEU; United States; Remote; USD 140,000 - 220,000; Full time

Job summary

IntellectEU is seeking a senior backend engineer to design and operate scalable, API-first services that interact with blockchain networks. You will implement secure communication, event-driven processing with Kafka, and robust multi-threaded solutions.

The role emphasizes observability, OpenTelemetry, and strong documentation practices. Ideal candidates have 7+ years in regulated environments, deep Java/Spring Boot expertise, and experience with Web3 libraries.

Qualifications

• 7+ years of software engineering experience in production-grade backend systems.
• Experience with blockchain, smart contracts, or tokenization platforms.
• Proficient in Java and Spring Boot; comfortable with polyglot stacks.

Responsibilities

• Implement and operate backend services with fault tolerance, security, and scalability.
• Build API-first services integrating blockchain networks and internal systems.
• Apply zero-trust security principles and cryptographic signing for secure service communications.
• Run event-driven architectures using Apache Kafka and asynchronous messaging.
• Ensure high availability and strong consistency in distributed services.
• Develop robust multi-threaded and asynchronous processing patterns.
• Integrate Web3 SDKs for on-chain interactions and transaction signing.
• Implement logging, tracing, metrics, and OpenTelemetry instrumentation.
• Maintain high test coverage with CI/CD-driven testing frameworks.
• Create API specifications and operational runbooks.

Skills

Java

Spring Boot

API design

Microservices

Concurrency

Distributed systems

OpenTelemetry

CI/CD

Software architecture

Documentation

Web3 libraries

Education

Bachelor's degree in Computer Science or related field

Tools

Kafka

REST/HTTP

CI/CD pipelines

DevSecOps

Web3.js

Ethers.js

Job description

Location

US, remotely

Responsibilities

• 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.

Requirements - Must Have

• 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).

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.

Nice to Have

• 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.

We guarantee:

• Global client interaction in a dynamic company serving the market for 15+ years with offices in Miami, Antwerp, Leuven, Lisbon, Viseu, Kyiv, Krakow, and New York.
• 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.

By submitting your application, you acknowledge that the company processes your personal data for recruitment purposes based on pre-contractual steps and legitimate interests. Your data may be shared with authorized personnel and service providers, including BambooHR, and transferred internationally with appropriate safeguards. We retain applicant data for up to 24 months unless otherwise required by law or requested for earlier deletion. For more details, see our Privacy Policy.

Originally posted on Himalayas