Senior Java Backend Engineer - Scalable, Global Systems

Joybuy; Greater London; On-site; GBP 110,000 - 150,000; Full time

Job summary

Joybuy in London is seeking a senior backend architect to lead technical decisions and shape the architecture of our international core systems. You will combine hands-on coding with strategic planning to ensure performance, security, and scalability.

The role emphasizes Java and Spring Boot, collaboration across global teams, mentoring engineers, and delivering robust, reusable frameworks. On-site work in London is required.

Qualifications

• Bachelor’s degree in Engineering, Computer Science, Mathematics, or a related technical field.
• 5+ years backend development with strong Java, JVM fundamentals, concurrency, multithreading, and performance tuning.
• Strong server-side architecture with MySQL, Redis, Kafka, and distributed systems in high-availability, high-concurrency environments.
• Excellent coding standards with a passion for technology and open-source learning.
• Strong analytical, problem-solving, and learning abilities with a proactive mindset.
• Demonstrated team leadership experience and effective communication in Chinese and English.

Responsibilities

• Lead technical decision-making and architecture design for JD’s international core systems, ensuring high standards of performance, availability, concurrency, security, and scalability.
• Design and oversee complex system architectures and drive productization efforts, maintaining architectural quality through hands-on coding, continuous performance evaluation, and system optimization.
• Architect and develop backend services using Java and Spring Boot, establishing engineering best practices and reusable technical frameworks.
• Build and maintain backend systems for JD’s operation centres, ensuring seamless integration across global infrastructure.
• Identify, assess, and mitigate technical risks throughout project implementation, covering monitorability, maintainability, grey release strategies, and rollback capabilities.
• Research, evaluate, and promote new technologies and methodologies, identifying integration opportunities within global architectures to strengthen the team’s technical capability and architectural foresight.
• Provide technical leadership, mentor engineers, and continuously optimize team collaboration and engineering best practices.
• Work onsite in London, UK.

Skills

Java

Concurrency

Multithreading

Performance tuning

Server-side architecture

MySQL

Redis

Kafka

Distributed systems

Leadership

English/Chinese communication

Education

Bachelor’s degree in Engineering, Computer Science, Mathematics, or related technical field

Job description

Joybuy in London is seeking a senior backend architect to lead technical decisions and shape the architecture of our international core systems. You will combine hands-on coding with strategic planning to ensure performance, security, and scalability.

The role emphasizes Java and Spring Boot, collaboration across global teams, mentoring engineers, and delivering robust, reusable frameworks. On-site work in London is required.