⚠️ AGENTS: DO NOT UPLOAD CVs DIRECTLY

Engineering candidates must start with a coding test. Please email recruit-engineer@hennge.com to receive an entry code and submission instructions. Direct ATS uploads will not be reviewed.

【重要：エージェントの皆様へ】 Greenhouse経由での直接の候補者推薦（CVアップロード）はご遠慮ください。

エンジニア職の選考はコーディングテストから開始いたします。まずは recruit-engineer@hennge.com までご連絡いただき、テスト用のエントリーコードと提出方法の指示を受け取ってください。手順に沿わない直接のアップロードは、選考対象外となる場合がございますので予めご了承ください。

About HENNGE

Join us at HENNGE, a Tokyo-based cloud-security company with the No. 1 IDaaS revenue share*, helping organizations adopt flexible work environments and safely leverage the cloud. As a B2B SaaS company, we build secure and reliable cloud solutions that help customers manage access and identity efficiently. Our flagship product, HENNGE One, empowers customers with access control, email filtering, archiving, and next-gen cloud security features. What makes us unique: a highly technical CEO, strong engineering culture, and a global mindset. For further details regarding the engineering teams, products, and more, please visit this link: https://speakerdeck.com/hennge/company-introduction-deck-hennge

*No. 1 IDaaS vendor by revenue share, FY2021–FY2025 (forecast), per ITR Market View 2026.

Role overview

We are looking for a Senior Frontend Engineer to lead the frontend development of Tadrill, a specialized platform designed to build organizational resilience by equipping employees to identify and neutralize cyberthreats, especially phishing attacks. As a core component of HENNGE One Cybersecurity Edition, Tadrill transforms employee behavior through continuous, practical attack simulations, automated e-learning, and seamless reporting flows via Gmail and Outlook extensions. In this role, you will architect a high scale and self managed framework, turning complex security data into actionable insights through intuitive dashboards while serving as both a technical owner and a catalyst for team engagement.

While this role primarily focuses on the Cybersecurity 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

Svelte w/ SvelteKit, Typescript, Playwright, Chromatic, Sentry, Go, AWS

What you’ll do

Design, build, and ship new frontend features for the Tadrill platform, ensuring a high-quality user experience.
Monitor, test, and improve the existing codebase to maintain speed and stability as the product scales.
Collaborate closely with Backend Engineers, Designers, and Product Managers to turn requirements into practical, high-quality code.
Identify areas for optimization across the entire application lifecycle to improve development efficiency and end-to-end performance.
Participate actively in code reviews, technical discussions, and documentation to ensure long-term maintainability.
Mentor junior engineers and contribute to a communicative, connected, and curious team environment.

What we’re looking for

Minimum Qualifications

3+ years of professional experience in frontend development with a strong focus on modern frontend frameworks (Svelte, React, Vue, Solid, Angular etc.)
Either have used Svelte professionally, in personal projects or have strong interest in working with it.
Proven track record of maintaining and scaling B2B SaaS products where stability and user-trust are paramount.
Experience leading technical initiatives or mentoring engineers in a collaborative, cross-functional environment.
High learning agility: the ability to dive into a specialized domain (Cybersecurity) and master a new stack with speed and curiosity.
A proactive "owner" mindset: you drive the success of a feature from conception to deployment.
Fluency in English (Japanese is not required), equivalent to CEFR B2 level or above (e.g., TOEIC 785+); an interest in working within a multicultural environment is essential.
Interest in contributing to open-source projects or participating in the tech community.