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 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.