TECH-Bizclo-01.Senior Fullstack Engineer (Bilingual –Japanese/English)_TokyoDev

◼︎Job Summary BizClo is an enterprise-focused LINE chat SaaS platform handling a massive volume of messages and high-traffic request processing daily. The product delivers experiences that improve operational efficiency and drive sales through 1-to-1 communication. In this role, you will tackle challenges such as modernizing and refactoring increasingly complex internal and customer-facing features, improving developer experience, balancing real-time responsiveness with system stability, and paying down technical debt. ◼︎Key Responsibilities <Architecture Design> Drive system design and development with an emphasis on modularity and reusability to accommodate flexible customer requirements. Actively work on design improvements based on current architecture and challenges. <Performance & SRE> Lead continuous improvements based on various metrics to enhance service responsiveness and stability, and establish and execute operational indicators. <Design System Promotion> Manage a shared foundation that connects design and implementation while maintaining UI quality. <DevEx Improvement> Improve developer experience by shortening build times, refining review processes, and expanding automation. <Technical Leadership> Facilitate environments that support technical decision-making and actively support the growth and mentoring of junior members. <Multilingual Communication> Collaborate and document effectively with global teams using both Japanese and English. ### Language and Platform - TypeScript - Node.js / pnpm / Turborepo ### Front-end - Next.js - Chakra UI / ShadCn ### Back-end - NestJS - Prisma ORM - Kafka、Redis、Elasticsearch ### Infrastructure and Operations - AWS（S3、Cognito、SQS） - Terraform、GitHub Actions ### Monitoring and Quality Assurance - New Relic、OpenTelemetry - Jest、Playwright、ESLint、Prettier

- Extensive practical experience (around 5+ years) in developing medium to large-scale web applications - Experience designing, implementing, and operating UI using React + Next.js - Experience designing and operating scalable backend systems using Node.js + TypeScript - Understanding of datastore design including RDB, NoSQL, and message queues - Experience with DevOps practices utilizing CI/CD and Infrastructure as Code (IaC) - Ability to conduct technical discussions and create documentation in both Japanese and English

- Experience leading improvements in development infrastructure, performance, and monitoring - Experience designing and improving real-time processing for high-traffic systems - Practical experience complying with security and privacy guidelines and regulations - Track record of external contributions (OSS, conference presentations, technical blogging)

- Ability to move forward from ambiguity and undefined situations with curiosity and drive - Balances technical decisions considering short-term effort and long-term value - Rapidly iterate on hypotheses and learn from failures - Sets high standards through code and reviews, inspiring the team - Identifies product challenges and follows through to completion - Collaborates with multinational members and openly shares knowledge