Senior Software Engineer (LINE API / LIFF App) at Yahoo!

Job description

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 As an integral part of Yahoo Inc. and Boundless Inc., our team develops a sophisticated search and display advertising management platform tailored for global clients expanding into the Japanese market. We provide a comprehensive suite of tools for automated high-volume ad data management and leverage cutting-edge AI to streamline complex business workflows. To accelerate our expansion, we are currently embarking on the development of next-generation systems designed to diversify and scale our revenue streams. A core initiative in this expansion focuses on leveraging LINE – Japan’s dominant messaging ecosystem – to build innovative, revenue-generating product features. To fuel this growth, we are seeking a talented and creative Senior Software Engineer based in Japan with proven experience using the LINE Messaging API and LIFF (LINE Front-end Framework). In this role, you will collaborate closely with cross-functional teams across both the U.S. and Japan to architect high-impact solutions, build scalable messaging workflows, and unlock new revenue channels for our business. Our Culture We operate as an agile, independent startup within Yahoo with unique business, spanning seven global locations with a remote-first and highly connected mindset. We seek engineers who are: Self-Driven Owners: You thrive on autonomy, taking full ownership of your work from concept to production. Global Collaborators: You excel at bridging distances, prioritizing proactive communication and seamless teamwork. Agile Thinkers: We value experimentation and iteration—we try fast, fail fast, and share what we learn to solve complex challenges. Responsibilities: Architect, develop, and optimize end-to-end systems for LINE messaging services and applications on AWS, leveraging agentic AI coding practices. Engineer new product features and operational tools to address the evolving needs of 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 and implementation details of existing platforms to ensure seamless integrations and ongoing system health. Continuously enhance core components of the whole ecosystem for improved performance and scalability. Work Schedule & Location Overlapping Hours: Because engineering team members 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. Qualifications: Core Requirements: Bachelor’s, Master’s, or PhD in Computer Science, or a related technical field. 8+ years of professional experience in software development. Active practice with – or a strong willingness to adopt – agentic AI coding techniques and workflows Deep experience in development using LINE messaging API, LIFF (LINE Front-end Framework), and LINE MINI App ecosystems. Hands-on experience with LINE SDKs, user authentication flows, and cloud application hosting on AWS or GCP Strong programming proficiency with Java, JavaScript, and TypeScript Deep understanding of algorithms and data structures Hands-on experience with relational databases and big data stores (e.g., MySQL, Oracle, or BigQuery) Experience with other LINE APIs is a plus Deep expertise in object-oriented programming, concurrency, distributed systems, and UNIX/Linux environments. Experience with design and development usin