Senior Software Engineer | Search, Data & AI Platform | Tokyo (Hybrid]

Finding the right information sounds simple—until you're doing it across billions of data points. We're looking for a Senior Software Engineer to help build the search and data platform behind a market-leading SaaS product used by businesses every day. You'll work on the systems responsible for indexing, searching, ranking, and processing massive volumes of information—building the foundation that enables fast, accurate, and increasingly intelligent product experiences. This role is ideal for engineers who enjoy solving difficult backend problems where performance, data quality, and scalability matter just as much as clean code. What You'll Build Design and develop large-scale search and data processing systems Improve search relevance, indexing performance, and system reliability Build backend services that power data-driven and AI-enabled product features Optimize distributed systems for performance, scalability, and operational excellence Collaborate with product, platform, and AI engineers to deliver meaningful customer value Contribute to architectural decisions, technical design, and long-term platform evolution What We're Looking For Strong professional experience building backend systems Proficiency in Java, Kotlin, Go , or another modern backend language Experience with search platforms, distributed systems, or data-intensive applications Solid understanding of system architecture, scalability, and performance optimization Experience working with cloud platforms such as AWS or GCP Business-level Japanese communication skills Nice to HaveExperience with any of the following is a plus: Elasticsearch, OpenSearch, Solr, or similar search technologies Distributed data pipelines or stream processing Information retrieval, ranking algorithms, or recommendation systems Machine learning or AI-powered product development High-scale SaaS or enterprise software platforms Why Engineers Join Work on complex search and data engineering challenges that go far beyond traditional backend development Build production systems where performance, accuracy, and scalability directly shape the user experience Collaborate with experienced engineers who value thoughtful architecture and technical excellence Influence technical decisions while remaining hands-on with design and development Hybrid working style, modern engineering practices, and opportunities for long-term technical growth Great software doesn't just store information—it helps people find exactly what they need, when they need it. If you're passionate about search, distributed systems, and building intelligent platforms at scale, we'd love to hear from you.