Full Stack Engineer, Tech Lead Track

**About the company:** KATIX Shibuya-ku, Tokyo KATIX makes selling your vehicle simple. Just take a photo and enter the details of it, and you'll receive offers from multiple companies for it. **Responsibilities:** Frontend and backend features across the platform in Next.js (App Router) and TypeScript, with Prisma and PostgreSQL Auctions, escrow, the seller upload and verification flow, buyer tooling, and internal dashboards The AI pipeline: verification of seller submissions (photos, documents) and price intelligence, built on foundation-model APIs (Claude, Gemini), plus the internal agents that help other departments ship AWS (ECS, RDS, S3), Docker, GitHub Actions; CI reliability and testing Kanban planning, daily standups, retrospectives Requirements 2 to 5 years of professional web engineering, full stack You work independently: you own features end to end, from an unclear request through design, build, review, and release Your code review is real. You give feedback that changes what ships, and you take feedback the same way You spot risks, blockers, and bad assumptions early and say so Solid grounding in a modern web framework (React or Next.js preferred), API design, relational databases, and data modeling Daily hands-on use of AI coding agents (Claude Code, Cursor, Copilot agent mode, or similar), including decomposing tasks for them and verifying their output Some experience mentoring or informally leading: reviewing for others, pairing, onboarding someone Clear communication with non-engineers, and genuine interest in the business side of what you build (the metrics your work moves: listing rate, closing rate, lead time to listing) Japanese at roughly JLPT N3 level. You can handle day-to-day casual conversation with colleagues outside engineering. Engineering discussions can happen in English. Nice to haves While not specifically required, tell us if you have any of the following. Evidence that you have accelerated your own or your team’s delivery with AI Hands-on Next.js, TypeScript, Prisma, or PostgreSQL Rails or Vue AWS beyond the basics (ECS, ECR, IAM), Docker in production Observability and reliability work (Sentry, New Relic, SLOs) Prior experience as a tech lead or team lead Marketplace, e-commerce, auction, or escrow-adjacent product experience Compensation ¥5,000,000 ~ ¥8,000,000 annually. **Requirements:** 2 to 5 years of professional web engineering, full stack You work independently: you own features end to end, from an unclear request through design, build, review, and release Your code review is real. You give feedback that changes what ships, and you take feedback the same way You spot risks, blockers, and bad assumptions early and say so Solid grounding in a modern web framework (React or Next.js preferred), API design, relational databases, and data modeling Daily hands-on use of AI coding agents (Claude Code, Cursor, Copilot agent mode, or similar), including decomposing tasks for them and verifying their output Some experience mentoring or informally leading: reviewing for others, pairing, onboarding someone Clear communication with non-engineers, and genuine interest in the business side of what you build (the metrics your work moves: listing rate, closing rate, lead time to listing) Japanese at roughly JLPT N3 level. You can handle day-to-day casual conversation with colleagues outside engineering. Engineering discussions can happen in English. **Nice to have:** While not specifically required, tell us if you have any of the following. Evidence that you have accelerated your own or your team’s delivery with AI Hands-on Next.js, TypeScript, Prisma, or PostgreSQL Rails or Vue AWS beyond the basics (ECS, ECR, IAM), Docker in production Observability and reliability work (Sentry, New Relic, SLOs) Prior experience as a tech lead or team lead Marketplace, e-commerce, auction, or escrow-adjacent product experience **Compensation:** ¥5,000,000 ~ ¥8,000,000 annually.