Senior Java Backend Engineer - Wallet & Blockchain

United States Digital Space LLC; Hong Kong; On-site; HKD 600,000 - 900,000; Full time

Job summary

United States Digital Space LLC is seeking a Senior Java Engineer to own core wallet backend modules in a high-concurrency, multi-chain environment. You will design, implement, and optimize address management, transaction flows, and on-chain interaction, ensuring reliability and performance across systems.

Ideal candidates have ~5–10 years of Java backend experience, strong fundamentals, and are comfortable driving complex designs and cross-team collaboration in a blockchain wallet context

Qualifications

• 5–10 years of Java backend experience required.
• Strong understanding of concurrency, JVM, and performance issues.
• Proficiency with Spring Boot and Spring Cloud or similar stacks.
• Experience designing and implementing medium-to-large backend modules.
• Familiarity with wallet, blockchain, or on-chain transaction flows is a plus.

Responsibilities

• Own core wallet backend modules and ensure reliability.
• Build and optimize address management, asset synchronization, and on-chain interaction scenarios.
• Support multi-chain integration and onboarding of new networks.
• Diagnose issues such as stuck transactions, duplicate submissions, and state discrepancies.
• Collaborate with product, QA, and infrastructure to drive delivery and improvements.

Skills

Java backend

Spring Boot

Spring Cloud

MyBatis

Concurrency

Performance tuning

Job description

United States Digital Space LLC is seeking a Senior Java Engineer to own core wallet backend modules in a high-concurrency, multi-chain environment. You will design, implement, and optimize address management, transaction flows, and on-chain interaction, ensuring reliability and performance across systems.

Ideal candidates have ~5–10 years of Java backend experience, strong fundamentals, and are comfortable driving complex designs and cross-team collaboration in a blockchain wallet context