[Hiring] Senior Software Engineer @Yahoo

Role Description

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.

• 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.

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.
• Strong programming proficiency with Java, JavaScript, and TypeScript.
• Experience designing REST APIs and running containerized (Docker) applications on AWS or GCP in Linux environments.
• Solid grounding in object-oriented design, concurrency, and distributed systems.
• Strong foundation in algorithms and data structures, with hands-on experience in relational databases (e.g., MySQL, Oracle) and/or large-scale data stores (e.g., BigQuery).
• Experience with other LINE APIs is a plus.

Requirements

• Excellent technical analysis, problem-solving, and communication skills.
• Proactive mindset with a strong sense of end-to-end ownership.
• Business-level Japanese and English, both spoken and written.

Work Schedule & Location

• Overlapping Hours: Engineering team are based in both Japan and the United States, this role requires working from 6:00 AM JST (Tuesday through Friday) to maintain sufficient overlapping hours with U.S. based colleagues. Mondays follow standard local working hours.
• Work Arrangement: This position is primarily remote (work-from-home), with occasional in-office meetings or team gatherings in Japan.