Required:

Senior Java Backend Engineer, English B2+

Full-time, EU working hours

Location: EU / Ukraine

Duration: Long-term (9+ month)

Responsibilities

Design and develop scalable backend services and microservices in Java/Spring Boot

Build and maintain blockchain integrations across multiple networks (Bitcoin, Ethereum, Solana, TRON)

Develop and support custodial wallet systems

Ensure reliability, security, and performance of blockchain-related infrastructure

Collaborate with cross-functional teams on architecture and technical decisions

Participate in code reviews and knowledge sharing

Requirements (Must-have)

Strong hands-on experience with Java and Spring Boot

Proven experience building microservices architectures

Hands-on experience with blockchain integrations (Bitcoin, Ethereum, Solana, TRON)

Experience with custodial wallet systems

English B2+

Nice to Have

Experience with additional blockchain protocols or Web3 ecosystems

Familiarity with security best practices in crypto/fintech environments

Tech Stack

Java, Spring Boot, Microservices, Bitcoin, Ethereum, Solana, TRON, Custodial Wallet Systems

Hiring Process

Intro call

Technical discussion

Offer

Start: ASAP