【AI Engineer】~¥18M | Popular AI SaaS

This record-breaking AI company with headquarters in the US and Japan ranks among the country's top profitable AI companies. With a continuous global expansion underway, they’re now looking for an AI Engineer to help advance their Search and Recommendations capabilities.

The Search & Recommendation Group develops core features that power multiple fast-growing AI products, including search, recommendation, and agent capabilities. The Senior Software Engineer will design and improve critical systems that enhance retrieval and recommendation performance, directly influencing the quality of AI-assisted workflows.

Key Responsibilities:

• Design, develop, and deliver large-scale search, recommendation, and agent-related APIs and features
• Work closely with product managers to define requirements and maximize customer value
• Diagnose and resolve performance bottlenecks in LLM-based and search-driven applications
• Maintain and enhance production systems to ensure stability and scalability
• Collaborate across teams to identify and quantify issues, define evaluation metrics, and implement measurable improvements
• Support sustainable, maintainable system architecture and mentor team members in software design best practices

• Bachelor’s degree in Computer Science, Mathematics, or a related technical field
• 5+ years of experience in software engineering or search system development
• Strong understanding of data structures and algorithms
• Practical experience designing reliable, high-performance web backend systems
• Hands-on experience with at least one major cloud platform (AWS, GCP, or Azure)
• Business-level Japanese proficiency (JLPT N2 or equivalent)

Nice-to-Haves

• Master’s or Ph.D. in a related field
• Practical experience with Apache Lucene, Elasticsearch, or Solr
• Hands-on experience with agent frameworks (LangGraph, Ragas, LlamaIndex, etc.)
• Proficiency in Python or Java
• Background in machine learning or natural language processing
• Experience mentoring junior engineers or leading large-scale projects (10+ members)
• Strong communication skills in multicultural teams (Japanese and English)
• Curiosity and passion for adopting new technologies such as AI-assisted development