Backend Technical Lead

This role leads backend engineering for DealOn, a new AI product focused on sales operations. DealOn was released as an MVP in April 2026 and is being expanded toward a system in which AI collects data, provides insights, designs next actions, and carries them out. The product includes an AI sales manager for decision-making and an AI sales assistant for task execution.

The technical lead is responsible for guiding development from requirements clarification and technology selection through architecture design, implementation, testing, and operations. The role establishes an architecture and development organization that can continue delivering value while balancing speed and quality during an uncertain new-business phase. Responsibilities include making technical decisions, setting design principles and development processes, and building systems with extensibility, maintainability, and stability in mind.

The work includes long-term domain modeling, data modeling, and API design; schema-driven development; shared-library development; CI/CD; and the creation of monitoring and operations foundations. The role also leads management of technical debt and architectural improvements aimed at future scalability and reliability. Code reviews, design reviews, technical consultation, and engineering decisions are used to improve team capability and development quality.

AI-driven development is a core part of the working approach. Claude Code and Codex are named as AI coding agents to be used for implementation, review, and incident response. The technical lead will organize workflows for these activities and help establish development processes and culture based on AI-assisted work, including AI review, investigation of defects, planning of corrective actions, and final human verification. The role may also design and operate workflows that orchestrate multiple AI agents for parallel development.

The main product engineering priorities are improving the accuracy of sales judgments and action recommendations through LLM design, evaluation infrastructure, and the incorporation of domain knowledge; expanding AI coverage from email creation, scheduling, and CRM entry to the broader sales process; and strengthening integrations with CRM, SFA, and communication tools. The role may also contribute to frontend and UI/UX design when needed, taking a product-wide view to improve user experience and output quality.

The position is based in Sakuragaoka, Shibuya, Tokyo. Full remote work is not available. The source does not state a salary, employment type, education requirement, experience threshold, or language requirement.