This position is closed and is no longer accepting applications.

Software Development Engineer in Test (SDET)

KOMOJU Musashino-Shi, Tokyo July 21 2025
  • 💴 No salary range given
  • 🏡
    Fully remote
    From Japan
  • 🌏
    Apply from abroad
    Relocate to Japan
  • 💬
    No Japanese required
    Business English
  • 🧪
    Intermediate level
    2+ years experience required

About KOMOJU

KOMOJU Musashino-Shi, Tokyo

The leading cross-border payment gateway for Japan. We power payments for companies like video game distribution platform Steam and the popular mobile app TikTok.

Key benefits

  • Developer-centric, inclusive culture
  • International at our core
  • Generous holiday policy

About the position

We are looking for passionate SDETs to join KOMOJU’s growing QA team. In this hybrid role, you will contribute to both automated and manual testing efforts to ensure the reliability, functionality, and performance of our payment systems.

As an SDET, you will help shape and drive QA processes from the ground up. You will be working cross-functionally with engineers, product managers, and business stakeholders to define and measure quality at every level of our stack. This is a great opportunity for someone who thrives in a collaborative environment and is eager to grow their technical and testing skills.

Responsibilities

  • Design, develop, and maintain automated test frameworks and tools to improve test coverage and reliability.
  • Execute and manage manual, exploratory, and regression testing for new features and releases.
  • Analyze system specifications and technical requirements to provide feedback and ensure testability.
  • Identify, document, and track bugs through resolution, contributing to improved product quality.
  • Support the team by building and maintaining CI/CD test pipelines and integrating automated tests into release workflows.
  • Collaborate with developers to ensure proper testing is done throughout the development lifecycle.
  • Participate in code reviews and test plan reviews.
  • Help establish quality processes and best practices across the engineering team.
  • Investigate and recommend tools or practices that help scale QA and improve team productivity.

Requirements

  • 2–5 years of experience in software testing, automation, or software development.
  • Proficient in at least one programming language (e.g., TypeScript, JavaScript, Python, or Ruby).
  • Hands-on experience with automated testing tools such as Playwright, Selenium, Capybara, or RSpec.
  • Strong understanding of testing methodologies including unit, integration, and E2E testing.
  • Experience writing and executing test plans and test cases, both automated and manual.
  • Familiarity with CI/CD pipelines and test automation integration.
  • Ability to work independently in ambiguous environments with a strong bias toward action.
  • Excellent communication and debugging skills.

Nice to haves

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

  • Experience testing multilingual or mobile applications.
  • Familiarity with AWS, monitoring tools like Datadog, or performance testing.
  • Exposure to backend systems, APIs, or infrastructure.
  • Experience working with agile teams or in fast-paced startup environments.
  • Open-source contributions.

Hiring Process

  1. 1

    Initial screening call with HR

    To understand candidates’ overall professional background, career aspirations, and to evaluate the fit for the role/ culture.

  2. 2

    Take-home exercise

    It’s opportunity to evaluate candidates’ practical experience and observe that they follow best practices.This includes, but is not limited to, their coding skills, problem-solving abilities, system design capabilities and ability to optimize and maintain code. We normally give the applicant one week to complete it, but we don’t expect it to take more than 2 hours.

  3. 3

    Technical team interview

    This interview serves two purposes: it’s a chance to review the take-home exercise and assess the candidate’s technical abilities, and it also helps evaluate their soft skills, how well they collaborate with stakeholders and team members, manage their work (time management, prioritization, adaptability), and demonstrate a commitment to continuous learning.

  4. 4

    Final interview with leadership

    We’re looking here to assess culture add. We’re not looking for people that just fit the status quo (culture fit), we want candidates who can bring something new and valuable to our culture. While ensuring that they still align with our core values, we want to assess their ability to adapt to recent changes within the organization and to help guide the organization through its next stage of development.

Meet KOMOJU's Developers

Kazunori initially joined KOMOJU as a web application engineer, but by identifying problems he wanted to fix, his role shifted first to VP of Infrastructure, and then VP of Payment Products.

Read their story...

Nicole joined KOMOJU in 2020, and worked her way up to be technical lead of the merchant management team. She shares her journey, how KOMOJU supported her career growth and how the company is adapting to its growing needs.

Read their story...
Photo of Richard Ramsden

Becoming CTO of KOMOJU

with Richard Ramsden

After graduating from university, Richard came to Japan and found a job as a software developer. Eventually he joined KOMOJU, where he rose to the role of CTO.

Read their story...

Nigel was fresh out of college when he joined KOMOJU as a developer. He's now risen to tech lead, where he's helped build out their payment platform while maintaining a healthy work-life balance.

Read their story...

Muhammad Denaw, Senior Site Reliability Engineer at Komoju, talks about his work and shares how Komoju's trust and support propelled him to a promotion.

Read their story...

Head of Customer Engineering Makoto Mizukami describes the unconventional candidates his unique team is looking for.

Read their story...

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