Senior AI Engineer (Ruby/Rails, TypeScript/React)

Location: Tokyo, Japan; 3 days per week in the Tokyo office. Infrequent travel to Mountain View, California may be required, usually for one week or less per year.

Company

hirify.global develops an agentic experience platform that helps marketing and data teams use autonomous, ROI-driven AI agents across web, mobile, and desktop workflows.

What you will do

• Lead the design and implementation of LLM integrations, retrieval-augmented generation, agentic pipelines, and AI-augmented workflows.
• Design, evaluate, iterate, and document prompt engineering approaches using production signals.
• Establish integration patterns for streaming responses, function calling, context-window management, fallback handling, and evaluation.
• Build and deploy AI capabilities for the customer-facing agent platform using Ruby/Rails and TypeScript/React.
• Scope AI feature work within a three-week delivery cadence and ship iterative improvements based on real usage.
• Own on-call shifts, conduct deep code reviews, and help teammates develop AI engineering skills.

Requirements

• 4–7 years of software engineering experience with a significant focus on AI/ML features or LLM-powered products.
• Strong proficiency in prompt engineering, LLM API integration, and building reliable production AI features.
• Experience with RAG, agentic workflows, or function-calling and tool-use patterns.
• Experience selecting between prompting, RAG, fine-tuning, and agentic approaches based on production constraints.
• Solid full-stack skills in Ruby/Rails and TypeScript/React, plus fluency with Claude Code, GitHub Copilot, and the customer-facing agent platform.
• Experience with systematic LLM evaluation, production monitoring, latency and cost management, multi-tenant routing, and customer data boundaries.

Culture & Benefits

• Work in a collaborative pod of 3–4 people with shared ownership of AI systems.
• Contribute to a culture centered on integrity, reliability, openness, humility, initiative, and customer focus.
• Participate in code reviews, pairing, documentation, and cross-pod AI engineering discussions.
• Work in an environment committed to diversity, equity, inclusion, belonging, growth, and ownership.