English summary for screening — check the original posting before applying.
Number Nine is seeking a Senior Full-Stack Engineer to join their development team. The role focuses on enhancing the reliability of the system infrastructure and establishing a sustainable development framework. You will work on core systems for content, contracts, royalties, and payments, as well as data/analytics and user-facing components for creators and readers.
Must-haves
- Experience launching a web service from scratch or developing/operating a large-scale web service.
- Several years of experience in team lead or product lead roles.
- Ability to flexibly handle different languages and environments by grasping the essence of problems.
- Mindset to solve problems across front-end, back-end, and data domains.
Nice-to-haves
- Experience with generative AI and AI coding tools for development and productivity improvement.
- Development experience with modern tech stacks (Go, Rust, TypeScript, Next.js, React, etc.).
- Experience developing business/core systems such as contracts, billing, payments, and accounting integration.
- Experience with data pipelines, BI, and SQL analysis.
- Knowledge/experience with schema-driven development and Domain-Driven Design (DDD).
- Interest in the publishing, manga, or creator ecosystem.
Tech stack
Next.jsReactTypeScriptGoRustProtocol BuffersConnect RPCMySQLDuckDBAmazon S3Cloudflare R2AWSCloudflareVercelDockerTerraformNx monorepopnpmGitHubVitestPlaywrightCucumberAnthropic Claude CodeOpenAI Codex
Work style
Hybrid work style in Tokyo (Shinagawa-ku). Core hours 10:00-16:00, flexible start/end times.
Other notes
Salary: 7.28 million - 10 million JPY per year. Includes fixed overtime allowance for 40 hours. Overtime beyond that is paid separately. Employment type: Full-time or contract employee.