Backend Engineer AI-driven SaaS

About The Role

• Develop backend systems for an AI-powered SaaS product
• Work with large-scale enterprise data and implement LLM-based features
• Work on a proven product with real users and real impact
  
  

• Backend development using Python (FastAPI) and TypeScript
• Design and implement LLM-based features
• Improve APIs, data models, and overall system performance
  
  

• Python (FastAPI), TypeScript (Next.js), SQL
  
  

• PostgreSQL
• Elasticsearch / OpenSearch
  
  

• AWS, GCP, Fastly
  
  

• GitHub, Slack, Notion, Asana, Google Workspace
• Cursor / Claude Code (AI-assisted coding, refactoring)
• CodeRabbit (AI-based PR review)
• n8n (AI workflow orchestration)
  
  

• Experience in backend development
• Experience designing APIs and databases
• Experience working in an agile development environment
• Currently residing in Japan, or willing and able to relocate to Japan
• Business-level Japanese communication skills (equivalent to JLPT N1)
  
  

• Experience with AI / LLM-related development
• Experience in architecture or system design
• Experience working at a startup
  
  

• Employment type: Full-time
• Salary: JPY 4,000,000 – 9,000,000 (depending on experience and skills)
• Fully remote work within Japan
• Full flex-time system (no core hours)
• Stock options available
  
  

• Work on real-world AI products used by real businesses
• Build systems handling large-scale data and LLM-based intelligence
• Join a startup that already has PMF and is entering a major growth phase
• Shape both the product and engineering culture from an early stage