Haken Application Engineer Java PHP - Tokyo

Join one of Japan's leading e-commerce and digital technology ecosystems as a Senior Application Engineer, taking a key technical role in a major CaaS migration and cloud-native modernisation project.

Based in Tokyo, you will lead system architecture, application development and technical delivery as a high-traffic e-commerce platform transitions toward a modern containerised architecture. Working with Java, Spring Boot, PHP, Laravel, Docker and microservices, you will help modernise applications supporting millions of users across Japan.

This position combines hands-on application engineering with technical leadership. You will guide a small engineering team, oversee design and code quality, and collaborate with project managers and engineering leads to deliver a successful platform migration.

Please note: This opportunity is only available to candidates currently residing in Japan with valid work authorisation.

Key Responsibilities

• Lead system design, architecture, application development and testing for a large-scale CaaS migration project.
• Drive the transition of existing applications toward modern containerised and microservices-based architectures.
• Develop and maintain detailed technical documentation and provide operational support following the platform migration.
• Act as the technical lead for architecture, design and source code reviews, maintaining engineering and quality standards throughout the project.
• Lead and support a team of 2-5 engineers, providing technical direction and driving successful project execution.
• Collaborate closely with internal project managers and engineering leads to align technical activities with project timelines, priorities and milestones.
• Provide clear progress updates and communicate complex technical information effectively to both technical and non-technical stakeholders.

Required Skills and Qualifications

Experience:

• 7+ years of hands-on web application architecture, design and development experience.
• Strong development experience with PHP and Laravel.
• Strong development experience with Java and Spring Boot.
• Practical experience designing and implementing containerised environments using Docker.
• Hands-on experience designing and implementing microservices architectures.
• Technical leadership experience managing or guiding small engineering teams of approximately 2-5 engineers.
• Experience conducting architecture, technical design and source code reviews.
• Experience communicating project status, technical requirements and progress to non-technical project managers.
• Must currently reside in Japan with valid work authorisation.

Soft Skills:

• Strong technical leadership skills with the ability to guide and support engineering teams.
• Excellent problem-solving skills when working with complex application architecture and migration challenges.
• Ability to collaborate effectively with engineers, project managers and other internal stakeholders.
• Strong communication skills with the ability to translate technical information for non-technical audiences.
• Ability to maintain quality standards while managing technical priorities and project timelines.

Language Requirements:

• Japanese: Conversational level.
• English: Conversational level.

Preferred Skills & Qualifications

• Experience working on CaaS, cloud-native or application modernisation projects.
• Experience migrating large-scale applications from traditional architectures to containerised or microservices environments.
• Knowledge of modern cloud-native application architecture and deployment practices.
• Experience supporting high-traffic web applications or large-scale digital platforms.
• Experience providing operational support following major application or infrastructure migrations.

About the Company

Our client operates one of Japan's leading e-commerce and digital technology ecosystems, delivering large-scale consumer services used by millions of people.

The organisation continues to modernise its technology environment through cloud-native architecture, containerisation and microservices. This position provides an opportunity to work on a pivotal CaaS and application modernisation initiative, collaborating with experienced engineers and technology leaders on systems operating at significant scale.

You will join a collaborative engineering environment where technical expertise, system reliability and continuous improvement are central to the development of the company's digital platforms.

Why You'll Love Working Here

• Take a leading technical role in a large-scale CaaS and cloud-native architecture migration.
• Modernise high-traffic applications supporting millions of users across Japan.
• Work hands-on with Java, Spring Boot, PHP, Laravel, Docker and microservices.
• Build deeper expertise in containerisation, microservices and application architecture.
• Develop your career as a Technical Lead while guiding a small engineering team.
• Collaborate with experienced engineers and project leaders within one of Japan's largest digital technology ecosystems.

Don't Miss Out - Apply Now!