Mercari, inc.

Internet

SecurityEngineerInternship

Minato City, Tokyo, Japan TEMPORARY
Market Sentiment
HIGH DEMAND

Neural analysis suggests this role is
optimal for Entry candidates.

The Brief

“Security Engineer Internship at Mercari, inc.. Skills: Security design, Process reviews, Security countermeasures development and deployment, Penetration tests, Threat modeling, Security automation, Web and mobile application security testing, Monitoring and log analysis, Vulnerability management. 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 f”

What You'll Achieve.

Identify and reduce risk in Mercari’s systems.; Propose actionable improvements for Mercari.; Help us build out our security systems and solve interesting challenges.

Industry & Context.

Internet
Problems you'll solve

Solve Through Mechanisms; Tackling complex security and infrastructure problems; Help us build out our security systems and solve interesting challenges in a fast-paced environment.

Eligibility Requirements

Must be able to stay in Japan, Visa support and accommodation arrangements provided for overseas candidates, Internship must be from within Japan

What They're Looking For.

Must Have

Shared understanding and belief in our company’s mission and values, 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

Nice to Have

Basic understanding or 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

What You'll Do.

Participate in threat modeling

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

Conduct focused security research on a supervised topic (e.g.

summarize key findings

and propose actionable improvements for Mercari.

Support vulnerability management processes by helping triage security findings

and coordinate with developers on remediation efforts.

Contribute to internal documentation

including secure development guidelines

AI security best practices

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.

How You'll Work.

Team & Collaboration

Collaborate openly; Coordinate with developers on remediation efforts; Work with experienced security engineers who are passionate about sharing knowledge and building the next generation of talent.; Team members are encouraged to contribute, ask questions, and grow.

Communication Scope

Effective interpersonal and communication skills; Independent (CEFR-B2) English or Japanese

Process & Methodology

Technical project management

Full Job Description

### JD in Japanese follows. 英文の後に和文JDをご覧いただけます。 ### Security Engineer – Mercari (Internship) * Target Applicants: Those who can join as new graduates in October 2027 or April 2028. * Employment Status: Intern * 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. * Regarding the arrangement of airline tickets, this applies only to those who have not purchased tickets at the time of the internship offer. * Work Hours: Able to work more than 20 hours per week 2-3 months of Internship is encouraged. * Office: in Japan (Remote or Roppongi) * Application Deadline: August 31, 2026, 23:59 (JST) * For more details, see the [Overview of Our Positions](https://careers.mercari.com/en/recruitment-selection/#section3) section on our Careers site. ### About Mercari Circulate all forms of value to unleash the potential in all people "What can I do to help society thrive with the finite resources we have?" 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. For more information about Mercari Group’s mission, see [Mercari’s Culture Doc](https://careers.mercari.com/en/culture/). ### Organization/Team Mission 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

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