Class of 2028 / New graduate Security Engineer

📋 Job Overview

Join Mercari Group as a Class of 2028 / New graduate Security Engineer. This role provides an environment where you can engage in experience design with a management perspective, not just engineering tasks, and grow into a leader who will drive the Mercari Group in the future. The position is based in Roppongi, Japan, with an application deadline of December 31, 2026.

🏢 About Mercari

Circulate all forms of value to unleash the potential in all people. The Mercari marketplace app was born in 2013 out of this thought by our founder Shintaro Yamada as he traveled the world. We believe that by circulating all forms of value, not just physical things and money, we can create opportunities for anyone to realize their dreams and contribute to society and the people around them. Mercari aims to use technology to connect people all over the world and create a world where anyone can unleash their potential.

🎯 The Role

As a member of the Mercari Security Engineering Team, you will review security designs and processes, develop and deploy security countermeasures, and conduct penetration tests. This is a unique role within Mercari because security engineers are involved in projects that impact the entire organization. You will work with cutting-edge infrastructure built on modern, cloud-native technologies and have the opportunity to tackle complex security and infrastructure problems at scale.

✅ Key Responsibilities

• Participate in threat modeling, code reviews, and security testing under the guidance of senior engineers to help identify and reduce risk in Mercari’s systems.
• Develop or enhance automation scripts for common security tasks such as compliance checks, asset inventory reconciliation, and alerting.
• Conduct focused security research on a supervised topic (e.g., AI system security, supply chain risks), summarize key findings, and propose actionable improvements for Mercari.
• Support vulnerability management processes by helping triage security findings, verify issues, and coordinate with developers on remediation efforts.
• Contribute to internal documentation, including secure development guidelines, AI security best practices, security playbooks, and onboarding material for engineers.
• Assist in security monitoring efforts, such as analyzing logs to detect anomalies, tuning detection rules, and helping track misconfigurations or policy violations.

📌 Required Qualifications

• Shared understanding and belief in our company’s mission and values
• Strong interest in cybersecurity and engineering
• Programming experience with one or more programming languages including but not limited to: Go, Python, PHP, JavaScript
• Enrolled in a Bachelor's degree (or higher) program or technical school in Computer Science, Information Security, or other engineering-focused major
• Effective interpersonal and communication skills
• Basic familiarity with Linux, including common commands and scripting
• Foundational knowledge of SQL and data querying

⭐ Desirable Experience

• Basic understanding or strong interest in any of the following:
• Experience attending or speaking at domestic and international security conferences, such as SECCON, Hardening Project, Black Hat, or DEF CON.
• Hands-on experience in security practices such as participating in CTF (Capture The Flag) competitions, bug bounty programs, or penetration testing.
• Knowledge of Web or mobile application security testing.
• Public cloud infrastructure platforms (GCP, AWS or Azure)
• Container and orchestration technologies (Docker, Kubernetes)
• Security automation and DevSecOps
• Experience leveraging AI for security operations automation and the protection of AI-driven systems
• Basic experience with software development tools such as Git, dependency management, build and deployment tools
• Understanding of modern Web or mobile applications

🎁 Benefits

Equal Opportunity Hiring: Mercari is committed to eliminating discrimination based on age, gender, sexual orientation, race, religion, physical disability, and other such factors so that anyone who shares our mission and values can join us, regardless of their background.

🛂 Visa & Eligibility

At Mercari Group, we value empathizing with and embodying the mission and values ​​of the Group and each company. To promote the creation of an organization that maximizes the total amount of value exhibited by all members, we would like to understand the experience and skills of each candidate as accurately as possible.