Skip to main content

Full-stack Engineer, Trust & Safety

5 day weekBuilt In Best Places '26Hybrid · Tokyo, Japan

Eureka is the company behind "Pairs," a dating and marriage matching app for people who are serious about finding a partner. Pairs is one of Japan's largest online dating apps, with over 27 million cumulative registrations in Japan. Since launching the Japanese version in 2012 and the Taiwan version in 2013, the service has grown steadily, with over 700,000 people finding a partner through Pairs. In 2015, we joined Match Group, which operates online dating apps around the world. To realize our mission of "creating things that people will be glad existed in their lives," we are aiming for further growth not only in Japan but globally.

Job Summary:

The Trust & Safety Project Team is dedicated to protecting users from violations and malicious activity, and to building and maintaining an environment where Pairs can be used with peace of mind. We contribute to the growth of the service by building robust and scalable foundations that support Trust & Safety operations—including detection, prevention, investigation, and response—thereby protecting users and enhancing the reliability of Pairs.

This position is for a Trust & Safety Engineer who will be a dedicated member of the Trust & Safety Project Team.

Your specific responsibilities will include the design, implementation, and improvement of web frontends such as management consoles, operational tools, and dashboards, enabling our internal operations team to make accurate and rapid decisions regarding detection, investigation, and response. You will also be responsible for the design, development, and operation of the backend systems that support these frontends. By leveraging insights gained from the field, you will directly improve the operational efficiency of our countermeasures.

Additionally, you will continuously review and analyze data regarding violating or malicious users, evaluate risks and impacts, and rapidly implement and improve the mechanisms that support detection, prevention, investigation, and response, contributing to the deterrence of malicious use and the protection of our users.

We expect you to work closely with team members in the Trust & Safety domain, using insights and data from the field to continuously improve the accuracy of our countermeasures and operational efficiency. Through these efforts, you will contribute to creating an environment where users can use Pairs with peace of mind.

What You’ll Do:

  • Design, implement, and improve management consoles and operational tools for the internal operations team responsible for detection, investigation, and response.
  • Build dashboards and monitoring UIs that visualize signs of risk and the effectiveness of measures.
  • Improve UI/UX to continuously enhance operational efficiency and decision-making accuracy in the field.
  • Design, build, and implement scalable APIs and data processing foundations that support the frontend.
  • Design, develop, and operate mechanisms that support Trust & Safety tasks such as detection, prevention, investigation, and response, and make continuous improvements in line with changing risk patterns.
  • Independently review and analyze data such as user behavior, system logs, and results of measures to evaluate signs of risk, trends, and the effectiveness of countermeasures.
  • Collaborate with stakeholders in the Trust & Safety domain, Data Analysts, product backend teams, SRE teams, and security teams to contribute to deterring fraud and abuse, protecting users, and improving the reliability of Pairs while enhancing quality, performance, security, and operability.

Basic Qualifications:

  • Experience implementing web frontends (SPA, etc.) using TypeScript (must be able to independently develop management consoles and internal tools).
  • 3+ years of experience in the implementation, release, and operation of commercial applications.
  • Experience building commercial Web APIs running on Public Clouds such as AWS or Google Cloud.
  • Strong motivation for improving development efficiency, performance, and security.
  • Ownership and communication skills to effectively involve stakeholders and achieve results.
  • Willingness to catch up on and learn about AI, and experience developing with Coding Agents.
  • Experience in building and designing various testing methods.
  • Experience in creating and operating commercial container images for web applications (e.g., Dockerfiles, installing necessary middleware).
  • Basic knowledge of middleware commonly used in web applications, such as Nginx and MySQL.
  • Japanese: Business level or higher; English: Conversational level or higher.

Preferred Qualifications:

  • Experience in continuously improving detection, prevention, and response mechanisms by independently analyzing data such as user behavior, system logs, and results of measures to evaluate risk signs, trends, and effectiveness in fast-changing risk areas like fraud, abuse, and policy violations.
  • Ability to independently extract, aggregate, and analyze data to a certain extent—while receiving support from Data Analysts as needed—to evaluate the scale of issues, priorities, the validity of countermeasures to be implemented, and the effectiveness of measures.
  • Experience in performing analysis and evaluation in environments where target user behavior and risk patterns change rapidly, and using those results to drive development and improvements.
  • Experience and knowledge in designing databases and applications with scalability in mind, considering large-scale data and access volumes.
  • Experience in improving development workflows, code quality, documentation, and team productivity by utilizing AI development support tools.
  • Building deployment scripts or Dockerfiles for applications in container environments.
  • Experience or knowledge in building infrastructure on Public Clouds such as AWS or Google Cloud.
  • Knowledge of basic security measures and requirements for web applications.

Tools we use: Programming Languages: Go, TypeScript/JavaScript, Python Tech Stack: MySQL,DynamoDB,Redis,Elasticsearch, Kubernetes,and various AWS and Google Cloud services,Terraform Development: Git,Github,GithubActions,Docker,Jira Cloud,Slack

#Eureka