Senior Software Engineer (Backend & Infrastructure)

About HENNGE

HENNGE is a B2B SaaS company based in Tokyo Japan, and we are at the forefront of the changing workplace. HENNGE One, one of the top cloud security services in Japan, allows customers to adopt flexible work environments and safely harness the power of the cloud from any location. With cloud security ensured, employees are free to focus on working smarter, improving quality, and achieving business results. For further details regarding the engineering teams, products, and more, please visit this link.

Position

We are looking for a Senior Software Engineer to take ownership of backend and web-platform development for HENNGE One, our flagship cloud-security suite serving over 2.8 million users globally. As a B2B SaaS leader in Japan, we provide mission-critical security solutions that empower enterprises to work safely from anywhere

In this role, you will join the Secure Transfer Team, responsible for the development of HENNGE One Data Loss Prevention (DLP) Edition. You will be developing our high-security file exchange solution—the "Secure Vault" of our ecosystem. Your mission is to architect the fault-tolerant, high-availability systems required to handle and protect sensitive enterprise data. This position is ideal for engineers who want to bridge the gap between advanced backend development and deep cloud infrastructure, utilizing tools like Kubernetes and Terraform to ensure data integrity.

While this role primarily focuses on the DLP Edition, we value engineers who are flexible and open to new challenges, with opportunities to move between teams and products through two-way discussions that support your growth and the company’s goals.

Tech Stack

FastAPI, Kubernetes, ArgoCD, PostgreSQL, AWS

What you’ll do

• Design, build, and maintain new features for HENNGE One, using Python and other web technologies.
• Architect scalable, fault-tolerant services deployed in cloud environments
• Automate deployment, testing, monitoring and documentation via CI/CD pipelines and infrastructure-as-code.
• Collaborate closely with Product Management, Design, and Customer Success teams to deliver high-quality user experiences.
• Participate actively in code reviews, discussions and technical decision-making.
• Mentor junior engineers, and contribute to improving team processes and engineering culture

Minimum Qualifications

• 3+ years of experience developing production-scale web applications using Python.
• Strong experience across the software development lifecycle (SDLC), from system design to deployment and maintenance.
• Hands-on experience with containerization and orchestration technologies (e.g., Kubernetes, ArgoCD).
• Experience with Infrastructure-as-Code tools, such as Terraform.
• Deep expertise in architecting and operating mission-critical AWS environments.
• Experience with CI/CD pipelines, automated testing, and clean-code practices.
• Ability to lead technical initiatives, mentor junior engineers, and work collaboratively in a team environment.
• Fluency in English (Japanese is not required), equivalent to CEFR B2 level or above (e.g., TOEIC 785+).
• Interest in contributing to open-source projects or participating in the tech community.

• Degree in Computer Science or related technical field.
• Experience building large-scale distributed systems or SaaS products.
• Familiarity of Go, or a strong interest in learning it, to help build and maintain our multi-language backend infrastructure.
• Additional experience with cloud security best practices, including PII obfuscation and secure data-handling protocols.
• Team leadership experience.

Reasons why you will enjoy working at HENNGE

• We Celebrate Diversity

• Smooth Japan Relocation

• Balanced Work Life

• Passion for Technology

• Collaborative Teams

Work in autonomous teams where your decisions shape our services. Influence every aspect of our products, from UX and architecture to development and deployment, in an agile and collaborative setting.

Work Style

Flexible working hours with a designated core time (11:00–16:00), allowing you to organize your day effectively. Employees typically work 8 hours per day with a 1-hour break.

Employment Type

Permanent employee.

Place of Work

Tokyo, Japan — Shibuya Headquarters.

Compensation

Annual salary: 8.5 to 12.5 million JPY

(includes English Allowance and Physical Communication Bonus)

Please refer to our Company Introduction Deck for an explanation of our Assessment System and the Belt System, which we use to determine the candidate's salary range:

Be part of a diverse and innovative team at HENNGE, where your passion for technology and desire to make a difference are valued and celebrated. Ready to change and challenge the status quo with us?

To learn more about life at HENNGE, please check these two links:

Hiring process

• Solve our online coding challenge

Complete our online coding challenge here

• you have fewer than three years of professional Python experience, and/or
• you complete the coding challenge using a programming language other than Python.
• Upload your CV and Cover Letter. Please check our guide on how to prepare them here:
• Casual interview with our HR
• 2 (or 3) interviews with our engineers (no live coding)
• Interview with our CEO

We value your time and want you to perform at your best, so the coding challenge will be the only technical assessment in the process. There will be no live coding sessions.

Have more questions? Please consult our FAQ.