Senior Rust Engineer

A Tokyo-based deep-tech startup is building a next-generation AI reasoning platform that enables artificial intelligence to solve complex, multi-step problems rather than simply generate text. Designed for enterprise customers in safety-critical industries, the platform combines advanced AI with transparent, verifiable reasoning.

We're looking for a Senior Backend Engineer (Rust) to help build the core backend infrastructure behind this technology. This role is based in Tokyo, Japan. Relocation is required, and the company provides full relocation support, including visa sponsorship.

Responsibilities

Develop core components of a distributed AI reasoning system.

Design, build, and maintain backend services, libraries, and platform infrastructure.

Own critical engineering components, ensuring scalability, reliability, and performance.

Build systems for understanding, processing, and reasoning about programming languages.

Collaborate with researchers and engineers on architecture and technical decisions.

Contribute to infrastructure for code analysis, automated reasoning, and AI-powered engineering workflows.

Requirements

5+ years of software engineering experience, including 2+ years working with Rust.

Strong backend development and distributed systems experience.

Experience building AI/ML infrastructure, scalable platforms, or other technically complex systems.

Solid understanding of software architecture and production-grade development.

Degree in Computer Science, Mathematics, Engineering, or a related technical field.

Strong ownership mindset and ability to deliver complex technical projects.

Excellent communication skills and English proficiency at C1 level or higher.

Nice to Have

Experience in startups or fast-paced product environments.

Experience with automated reasoning, code intelligence, developer tools, or AI systems.

Background in AAA game development or other highly complex software environments.

Experience with C++ or Python.

What the company offers

Competitive salary: 14-17M JPY gross per year (approximately $90-107K).

Full visa sponsorship and relocation support to Tokyo.

Comprehensive healthcare and Japanese social security.

Up to 25 paid vacation days per year.

English and Japanese language learning support.

High ownership, low bureaucracy, and the opportunity to work on cutting-edge AI technology.

If you're passionate about building high-performance backend systems and want to work at the forefront of AI infrastructure, we'd love to hear from you!