Senior Software Engineer (Python/Web Dev) - HENNGE Access Control

We’re looking for a senior software engineer to take ownership of backend and web-platform development. You’ll join the Access Control Team, responsible for HENNGE One Identity Edition, part of the HENNGE One suite serving over 2.8 million users. Your work will focus on developing core features like Access Control, Single Sign-On, and Secure Browser to deliver secure and seamless access experiences for enterprises. 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: Tornado, FastAPI, DynamoDB, PostgreSQL, AWS

If you are also interested in the Senior Software Engineer, Backend & Infrastructure Team – HENNGE Secure Transfer position, you do not need to submit applications for both roles. Since both positions share the same hiring pipeline, one application is sufficient. Please simply indicate your interest in both roles in your cover letter.

Responsibilities

- 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.

Requirements

- 5+ years of experience developing production-scale web applications using Python. Please note that your application will be automatically rejected if:

- you have fewer than five years of professional Python experience, and/or

- you complete the coding challenge using a programming language other than Python.

- Ability to mentor junior engineers and work collaboratively in a team environment.

- Hands-on experience with cloud infrastructure (AWS, GCP or Azure) and distributed system concepts.

- Experience with CI/CD, automated testing, code documentation, and clean-code practices.

- Fluency in English (Japanese is not required), equivalent to CEFR B2 level or above (e.g., TOEIC 785+).

- Interest in open source or tech community activities.

Nice to haves

While not specifically required, tell us if you have any of the following.

- Degree in Computer Science or related technical field.

- Experience building large-scale distributed systems or SaaS products.

- Knowledge of web-security, access-control, email-or-storage-systems domains.

- Knowledge of DevOps tools and practices (CI/CD, Infrastructure as Code).

- Knowledge of Linux / MacOS / Unix-like environments.

- Team leadership experience.