Senior Front-end Engineer (React)

About HENNGE

HENNGE is a leading cloud-based security provider in Japan, delivering an additional security layer to companies which move their operations to the cloud. Our service HENNGE One has over 70% market share for cloud security services targeting Microsoft 365/Google Workspace in Japan. We are growing fast and are a listed company on the Tokyo Stock Exchange.

As part of the engineering team, you will be responsible for building cloud-security solutions used by thousands of enterprise companies. Our flagship product, HENNGE One, provides functionalities ranging from access control, email filtering, online storage, and email archiving. We focus on implementing state-of-the-art security functionalities, ensuring SLA 99.9% in distributed fault-tolerant deployment, and providing the best user experience to our customers.

Position

We’re currently looking for a Senior Front-end Engineer (React) to join our fast-paced growing team. As part of the engineering team, you will be responsible for building cloud-security solutions used by thousands of enterprise companies. Our flagship product, HENNGE One, provides functionalities ranging from access control, email filtering, online storage, and email archiving. We focus on implementing state-of-the-art security functionalities, ensuring SLA 99.9% in distributed fault-tolerant deployment, and providing the best user experience to our customers.

Responsibilities

• Design, develop, and maintain innovative features based on business needs
• Bring our design system to life by implementing high-fidelity UI using a modern frontend framework
• Ensure high-quality deliverables through CI/CD pipelines, tests, and documentation
• Collaborate with Design, Product Management and Customer Success teams to continuously improve the product
• Support the team by actively participating in discussions and reviewing others’ code
• Improve team synergy and mentor junior engineers

Our Tech Stack

Each product team is free to choose their own tech stack. Each project uses Typescript as the base language, with a combination of these technologies:

React:

• Styled Components
• Redux (Toolkit)
• RxJS
• Jest/Testing Library
• Testcafe

For more information, you can also check our Stackshare page out.

Your qualification

Minimum Qualifications

• 3+ years of web development experience, with at least 3+ years in React
• Ability to write proper type-safe code with Typescript
• Ability to mentor junior engineers and work collaboratively in a team environment
• Ability to write robust tests along with your code
• Understand the importance of clean code and software documentation
• Business-level English (Japanese is NOT required)
• Interested in open source/tech community activities

Meet at least three of the following criteria:

• Degree in Computer Science or other related technical fields
• Experience with state management in a complex web app (e.g. Redux, Vuex)
• Familiarity with design collaboration tools like Figma
• Knowledge setting up build and test environments, CI/CD pipelines
• Knowledge of Unix-like environment
• Team leadership experience
• Experience with Function Components and Hooks

What we offer

• English Allowance and Advanced Language Expert Allowance: JPY 10,000 ~ JPY 130,000 per month, paid alongside base salary, if the employee fulfills the requirements.
• Physical Communication Bonus: JPY 4,000 per day* for coming to the office and interacting with other employees, paid out as bonus according to the number of days. (*Applicable from October 2025 onwards)
  Details will be provided at the offer meeting.
• Insurance: Health, Employment, Industrial Injury, Welfare pension
• Transportation allowance (maximum of JPY 35,000 per month)
• Employee Stock Ownership Plan
• Opportunities to attend international and domestic conferences
• Financial support for technical certifications and technical learning programs

Reasons why you will enjoy working at HENNGE:

• We Celebrate Diversity

  Join a vibrant team from over 20 countries, united by a love for technology and Japanese culture. Located in Shibuya, Tokyo, we offer a dynamic, non-traditional work environment in one of the world's most exciting cities.

• Smooth Japan Relocation

  We make your move to Japan smooth and stress-free. We provide comprehensive support such as flight tickets, visa sponsorship, and Japanese lessons, to ensure a smooth onboarding process for our new hires, ensuring a seamless transition and a warm welcome for all candidates.

• Balanced Work Life

  Work-life balance is highly valued at HENNGE, and lots of fun happens at our office! 200+ of social channels in our Slack, from weekly board game nights to snowboarding club, internal and seasonal events, monthly tech sessions with beer bashes, attendance of international tech conferences, and more. Employees have access to a flexible working hours system (with core working hours) to accommodate their preferred working style.

• Passion for Technology

  Our CEO, also serving as CTO, actively leads product development, fostering an environment of innovation and support. Having a leader who truly understands and is still involved in the tech side of the business makes for an exciting and supportive environment for engineers.

• 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.

   

  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?

Additional details

Working Conditions:

Employment Type

Permanent Employee

Place of Work

Japan, Tokyo, Shibuya HQ

Hybrid work environment with emphasis on in-office collaboration and encouragement for employees to work onsite.

Working Hours

10:00 - 19:00

- Flex Time (Core time is 11:00 - 16:00) with 1 hour break.

Remuneration

We generally offer a salary range of JPY 8.5M to 12.5M (English Allowance & Physical Communication Bonus inclusive - please check the details below), with the final amount determined based on your experience and skills.

- 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: https://speakerdeck.com/hennge/company-introduction-deck-hennge

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

• Life at HENNGE
• Stories from our employees

Selection Process

1. Solve our coding challenge by clicking the button below. You will receive an email with our guidance upon your submission, and there is no time limit to finish the challenge.

2. Once you finish the coding challenge, follow the instructions to upload your CV and Cover Letter.

3. Casual interview with our HR

4. 2 (or 3) interviews with our engineers

5. Interview with our CEO