Position: Senior Software Engineer – Search & AI
Company: Confidential Legal AI SaaS Company
Location: Tokyo, Japan (remote-friendly within Japan, no full remote)
Employment Type: Full-time
Overview
A rapidly growing legal technology company is seeking a Senior Software Engineer specializing in Search and AI to lead the development of intelligent document and contract analysis systems. Founded in Japan and expanding globally, the company operates a high-revenue, AI-first SaaS platform with strong momentum across international markets.
This role offers the opportunity to take ownership of core search and AI architecture within a complex domain involving large-scale document processing, permissions, and workflow systems.
Position Summary
The Senior Software Engineer will lead the design and development of search, recommendation, and AI-driven systems. This role focuses on building scalable, high-performance infrastructure while driving technical direction and mentoring engineers across teams.
Key Responsibilities
Search & AI Architecture
Design and develop search, recommendation, and AI agent systems
Lead architecture for intelligent document processing and analysis
Improve relevance, performance, and scalability of search systems
Technical Leadership
Define technical direction and best practices for search and AI systems
Mentor engineers and support team development
Lead large-scale technical initiatives across teams
System Optimization
Build reliable, high-performance backend systems
Optimize systems for scalability, latency, and accuracy
Ensure robustness in production environments
Innovation & Research
Evaluate and implement emerging technologies in search and AI
Contribute to continuous improvement of AI-driven product capabilities
Qualifications
Required
Bachelor’s degree in Computer Science or related field
5+ years of experience in search engineering or software engineering
Strong foundation in data structures and algorithms
Experience building scalable, high-performance backend systems
Cloud experience (AWS, GCP, or Azure)
Japanese proficiency (JLPT N2 level or equivalent)
Preferred
Master’s or PhD in Computer Science, Machine Learning, or NLP
Experience with search technologies (e.g., Lucene, Elasticsearch, Solr)
Experience building AI agent systems
Strong Python development experience
Background in machine learning or natural language processing
Experience mentoring engineers or leading teams
Experience leading large-scale technical projects
Familiarity with AI-assisted development tools and workflows
Technical Environment
Backend
Python-based high-performance backend systems
Search
Lucene, Elasticsearch, Solr (preferred)
AI
Modern AI agent frameworks and NLP technologies
Leadership
Technical strategy, mentoring, and cross-team execution
Working Style & Benefits
Flexible working hours (no core time / discretionary system)
Hybrid work model (remote-friendly within commuting distance)
120+ days off annually (weekends, holidays, additional leave)
Full social insurance
Sick leave, family care leave, parental leave, and additional benefits
Access to advanced AI and productivity tools
Development tools and engineering environment support
Learning budget and language support
Employee stock ownership plan
Side work permitted with approval
Non-smoking office (designated smoking areas available)
Compensation
10.3M – 19M JPY (depending on experience)
Career Path
Ownership of core search and AI infrastructure
Progression into Staff or Principal Engineer roles
Opportunities to influence global product and architecture strategy