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

Applications: candidates must already be in Japan. Visa sponsorship: not available. Japanese: Not required. English: Fluent. Japan Dev tags: Engineering, Front-end, React, Typescript, Vue, CI/CD.

Location requirement

You must already be living in Japan with valid work authorization. We are not sponsoring relocation or visa transfers from overseas for this role. Applications from outside Japan will not be considered.

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

• Currently based in Japan with valid work authorization — no relocation or visa sponsorship from overseas for this role
• 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
• Passion for continuous improvement and staying current with the rapidly evolving AI landscape

Note: You will be hired and supported by Abbeal (visa sponsorship + Mobbeal expat support).