AI Product Engineer

Loglass is developing the next generation of its Loglass Management cloud product for corporate management and budget-versus-actual management. As a core member of the product development team, the AI Product Engineer will lead feature development and improvement while the existing product undergoes large-scale rearchitecture and domain redefinition.

The role involves documenting and reviewing architecture decision records, advancing technology selection, and modeling and designing systems based on interviews about customers’ actual work. Responsibilities also include improving the speed of data aggregation and analysis displays, carrying out regular refactoring, leading projects within the development team, and accelerating, streamlining, and automating the development workflow. The engineer will also lead improvements to development processes across teams and work closely with product managers and domain experts.

The team is building an AI-native SaaS product and applying AI throughout the development lifecycle, from upstream design discussions through implementation and final quality assurance. The role includes leading technical decisions for complex domains and balancing system flexibility and long-term scalability with usability for end users. The posting describes work on a platform connecting customers’ data at its smallest level through to financial statements.

Required experience includes leading and promoting technical decisions that affect a wider organization than the immediate team; initiatives that improve team productivity through process improvement, enablement, and automation; at least approximately five years of server-side web application development experience; and at least approximately three years of test design and test-code experience. Experience with refactoring or rearchitecting legacy or large-scale systems and with agile development processes is also required. Desired experience includes frontend development, development with statically typed languages, AI-assisted development, TDD or DDD, and performance-focused coding.

The main development tools listed are Go, Kotlin, Rust, React, Next.js, TypeScript, Cursor, Claude Code, AWS with Kubernetes on EKS, Terraform, Aurora PostgreSQL, Datadog Synthetics, and Playwright. Other listed tools and services include Slack, Gather, Figma, Findy team+, Notion, diagrams.net, and Gemini.

This is a permanent full-time position in Minato, Tokyo. The stated hours are 10:00–19:00 with a one-hour break, under a flextime system with core hours from 10:00 to 15:00. The annual salary range is ¥8,000,000–¥20,000,000, determined based on experience and skills. The posting gives examples of monthly salaries of ¥667,000 for an annual salary of ¥8,000,000 and ¥1,667,000 for ¥20,000,000; each includes 60 hours of fixed overtime, with additional payment for work beyond the fixed overtime period. The probationary period is three months and may be extended to six months. Benefits include company-leased housing, assistance for PC-related equipment, and a corporate defined-contribution pension plan. Insurance includes health, employees’ pension, employment, and workers’ compensation insurance. Holidays include Saturdays, Sundays, public holidays, and December 28 through January 3, with annual paid leave, bereavement leave, childcare nursing leave, nursing-care leave, and menstrual leave. The possible workplace-change range includes company-designated locations, including a place where telework is performed. The posting also describes career changes from web application engineering into technical leadership, product development leadership, product management, engineering management, and common-platform engineering.