Backend Engineer

Location: Tokyo, on-site

Language: English required, Japanese a plus

Experience: 3+ years building backend systems and APIs

We're building a product-first company transforming how people file taxes—automating what others still do manually. Our app helps turn tax filing from slow and messy into something clear, fast, and (yes) enjoyable.

We're now hiring a Backend Engineer to join our high-ownership engineering team. You'll work alongside our lead backend engineer to expand what our platform can do—taking full ownership of projects as they're assigned, with clear success metrics, and seeing them through. This is a hands-on role for someone who wants to build meaningful systems in a fast-moving product company.

You'll work closely with engineers, product specialists, designers to ship features that matter—processing documents, expanding platform capabilities, and helping the team move faster.

What You'll Do

• Build and maintain backend features across our product
• Take full ownership of projects as they're assigned, including defining success metrics and seeing them through
• Design and maintain APIs consumed by our frontend
• Collaborate with the lead backend engineer on shared infrastructure and data models
• Handle data validation, error handling, and edge cases across complex workflows
• Contribute to backend architecture decisions as the product grows

What We're Looking For

• 3+ years experience building backend systems and APIs (Node.js, Python, or similar)
• Comfortable modeling business logic and working with structured and unstructured data
• Experienced with relational databases, data modeling, and query optimization
• Familiar with API design, authentication, and error handling
• Engineering mindset: attention to correctness, edge cases, and maintainability
• English required; Japanese a plus

Nice to Have

• Experience with OCR tools or document processing pipelines
• Experience in fintech, legal tech, or other compliance-adjacent domains
• Startup or small team experience

Why Join Us

• Real ownership: You'll own projects end-to-end with clear success metrics—not just tickets in a queue
• Meaningful problems: Document processing, data pipelines, and workflows that directly impact how people file their taxes
• Great team: Work directly with the founder and a senior backend engineer in a low-bureaucracy environment
• Work that matters: Build something people genuinely need—not just another CRUD app or internal tool
• Fast-moving environment: High iteration speed, direct feedback, real product impact

✏️ How to Apply

Apply via LinkedIn. Bonus points if you can share something you've built that shows your approach to system design and backend craft.