[English Only] Lead JavaScript SDK Engineer＠Best e-commerce

We are looking for a Lead SDK Engineer to drive the development of web-based SDKs and developer tools for a large-scale analytics platform. You will lead technical design, improve developer experience, and ensure seamless integration across multiple platforms.

Client Details

The client operates a large-scale data and analytics platform that aggregates online and offline user data for advanced analytics and marketing use. Their systems process billions of events in real-time and support critical business decisions across multiple services.

Description

• Lead development and maintenance of JavaScript/TypeScript SDKs for web applications
• Own and improve developer tools such as Chrome extensions and analytics debuggers
• Collaborate with cross-functional teams (Web, iOS, Android) for seamless SDK integration
• Design and implement features to enhance developer experience and platform usability
• Conduct code reviews and enforce best practices across the engineering team

Job Offer

• Long-term contract (initial 2 months, renewable every 3 months)
• Highly technical leadership role in a data-intensive environment
• Work on systems processing billions of daily events
• International, English-only engineering environment
• Working hours: 9:00 - 17:30 (Weekdays only)
• Location: Futako-Tamagawa, Tokyo
• Opportunity to influence developer experience at scale

To apply online please click the 'Apply' button below. For a confidential discussion about this role please contact Hikari Takamura on +813 6832 8903.

• 5+ years of experience in JavaScript / TypeScript development
• Strong experience in SDK development for web applications
• Proven experience leading development of widely-used SDKs
• Deep understanding of modern frameworks (React, Angular, or Vue.js)
• Experience with unit testing frameworks (e.g., Jest)
• Familiarity with build tools such as Webpack or Vite