Senior Software Engineer (LINE API / LIFF App)

Boundless Inc., part of Yahoo Inc (headquartered in the U.S.), is a trusted marketing and advertising partner empowering global companies to succeed in the Japanese market. With multilingual teams spanning key regions worldwide, we deliver end-to-end solutions driven by deep local insights and a global perspective.

About Our Team

We're part of Yahoo Inc. and Boundless Inc. We build a search and display advertising management platform for global clients entering the Japanese market. It includes tools that manage large volumes of ad data automatically and AI that simplifies complex business workflows.

We're now building new systems to add and grow revenue streams. A core part of this is LINE, Japan's leading messaging platform, where we're building new features that generate revenue.

We're looking for a Senior Software Engineer based in Japan with hands-on experience using the LINE Messaging API and LIFF (LINE Front-end Framework). You'll work closely with teams in the U.S. and Japan to design solutions, build messaging workflows that scale, and open new revenue channels for the business.

Our Culture

We work like an agile startup inside Yahoo, with teammates around the world and a remote-first way of working. We're looking for engineers who are:

• Self-Driven Owners: You take a feature from idea to production and keep improving it.
• Global Collaborators: You communicate proactively and in writing across time zones and cultures.
• Agile Thinkers: You ship small experiments, measure the results, and share what you learn with the team.

Responsibilities:

• Design, build, and optimize LINE messaging services and applications on AWS, using AI coding agents (e.g., Claude Code, Copilot agent mode) as part of your daily work.
• Build new product features and internal tools for our global clients.
• Partner with cross-functional stakeholders to identify user pain points and translate business requirements into robust technical specifications.
• Deeply understand the architecture of our existing ad platform well enough to build smooth integrations and keep the system healthy.
• Continuously enhance core components of the whole ecosystem for improved performance and scalability.

Must-Have Qualifications:

• Bachelor's degree in Computer Science or a related field, or equivalent practical experience.
• 8+ years of professional experience in software development.
• Deep hands-on experience with the LINE Messaging API and LIFF, plus proven experience building and launching LINE MINI Apps, including LINE SDKs and LINE Login/authentication flows.