Class of 2028 / Security Engineer Internship

📋 Job Overview

Security Engineer Internship at Mercari, focusing on security design, process reviews, security countermeasures, and penetration tests. The role involves high-stakes projects across the organization, with opportunities to work on topics like monitoring and log analysis, security review, and technical project management.

🏢 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.

🎯 The Role

This internship 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. For students aiming to become future product leaders, this internship offers the opportunity to take on challenges from both business growth and social problem-solving perspectives.

✅ 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
• Availability to work 20+ hours per week for a period of 2–3 months
• 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
• 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

Visa support and accommodation arrangements for those who live overseas. Regarding the arrangement of airline tickets, this applies only to those who have not purchased tickets at the time of the internship offer.

🛂 Visa & Eligibility

Please apply only if you are able to stay in Japan, as the internship must be from within Japan. For those who live overseas, we will provide Visa support and accommodation arrangements.