Senior Frontend Engineer (Vue.js / TypeScript) — Tokyo

Role Overview

This role is focused on building AI-powered tools that support sales enablement. As a Software Engineer, you will work on designing and developing product features that leverage AI technologies to improve how sales teams operate and create value for users. This is a high-impact position for engineers who are excited to work at the intersection of product development and applied AI.

Technologies

Core Stack:

• AI/LLM: OpenAI SDK, prompt engineering & optimization
• Backend: Node.js, TypeScript, Effect (functional TypeScript)
• Cloud: AWS (Lambda, DynamoDB, SQS, SNS, SES, CDK)
• Integrations: Google APIs (Gmail, Calendar), Microsoft Graph API, Zoom API
• Testing: Vitest
• CI/CD: GitHub Actions, pnpm

Note: The above technologies reflect our current stack. The team has the autonomy to make technology choices that best serve our AI-native product goals. You will be involved from the architecture and technology selection stage.

Key Responsibilities

• Design, build, and operate AI-powered systems leveraging large language models (LLMs), including prompt engineering, output parsing, and evaluation pipelines
• Architect event-driven workflows (Lambda, webhooks, queues) that enable AI-powered features to operate reliably at scale
• Collaborate closely with product, sales, and CS teams to translate business needs into effective AI-driven product features
• Own the full lifecycle of AI-powered products-from prototyping and prompt tuning to production deployment and monitoring
• Evaluate and integrate emerging AI capabilities (models, APIs, tooling) to continuously improve product and model performance
• Contribute to engineering best practices through code reviews, documentation, and knowledge sharing

Must Have

• 4+ years of software engineering experience in product development
• Hands-on experience building applications that integrate LLMs (e.g., Claude, GPT), including prompt design, tuning, and output evaluation
• End-to-end engineering experience from design and development through to production operation
• Solid backend engineering skills (Node.js/TypeScript preferred)
• Experience with event-driven or serverless architectures (Lambda, webhooks, message queues)
• Strong communication skills and comfort working with cross-functional stakeholders
• Business-level proficiency in both Japanese and English (for Japanese, a JLPT N2 or higher certification is required)
• Passion for continuous improvement and staying current with the rapidly evolving AI landscape