Backend Engineer (Langaku)

About Mantra

Mantra is a technology company building products that empower people through entertainment and education.

Our core services include:

MANTRA ENGINE : A machine learning–driven recommendation and personalization engine designed to optimize manga and content distribution.

LANGAKU : An innovative language learning app that allows users to learn English and other languages through manga, combining natural language processing and education technology.

Joining our engineering team means contributing directly to these services—designing, developing, and operating systems that reach users worldwide. You will work in a cross-functional environment where engineers, product managers, and designers collaborate to create user experiences loved by millions.

Primary Responsibilities

Develop and maintain the backend for mobile applications (e.g., supporting LANGAKU and other consumer-facing services).

Enhance productivity and quality through automation of testing and operations.

Build, maintain, and operate infrastructure and data analysis platforms (supporting MANTRA ENGINE and other internal systems).

Conduct data analysis to extract user issues and verify hypotheses.

Collaborate with product managers and designers to design user experiences and features that solve user problems.

Make technical decisions and build/manage development schedules.

Technical Stack

Frontend : Flutter (iOS, Android)

Backend : Python

Infrastructure : AWS, GCP

Basic Qualifications

3+ years of experience in backend development for mobile applications.

Experience with databases.

Preferred Qualifications

Experience in data analysis and building data analysis platforms.

Experience in building and operating infrastructure using AWS.

Knowledge and experience with server-side development using Django.

Experience in developing consumer-facing mobile applications.

Basic knowledge and experience in machine learning.

The Ideal Candidate

Someone accustomed to continuous learning.

Able to approach problems by formulating and then verifying hypotheses.

Enjoys communicating with people from different fields and backgrounds.

Able to take ownership and handle working independently.

Strong interest in Mantra's focus areas (manga, language, machine learning).

Benefits

Flexible working style, including remote work options .

Relocation and visa sponsorship support for candidates moving to Japan.

A collaborative, international team with members from diverse backgrounds.

Selection Process

Document screening (resume, detailed career and job history, portfolio)

~3 Interviews

Final meeting to discuss terms of employment and compensation