Custom AI Agent & AI/DX Development for Businesses in Japan

Sound familiar?

✓You want a custom AI agent that handles a specific job for your business
✓You want to connect ChatGPT / LLMs to your own documents and data (RAG)
✓You want to replace Excel and manual work with a proper app or system
✓Your PoC stalled and you need it taken to production
✓You need a partner who can build and operate it — in English, in Japan

If any of these apply, let's talk — the first consultation is free.

What We Build

We handle the whole thing — design, build, and operation — tailored to how your business works.

Custom AI Agents

Agents and assistants that learn your business and data, and handle a specific job on their own.

· First-line response to inquiries (email, chat, LINE)
· Drafting quotes, invoices, and reports
· Searching and summarizing internal knowledge
· Running routine tasks across multiple tools

Generative AI & LLM Apps

Apps built on ChatGPT-class LLMs, including answers grounded in your own documents (RAG).

· Q&A / chat over your internal documents (RAG)
· Document generation, summarization, translation, classification
· Generative AI embedded into your existing sites and tools
· Prompt design and accuracy tuning

Business Systems & Internal Tools (DX)

Replace Excel, paper, and manual work with a purpose-built web app, system, or dashboard.

· Internal web apps and admin panels
· Data aggregation and visualization dashboards
· Booking, inventory, and customer-management systems
· Automated recurring reports and documents

AI in Your Existing Systems

Add AI to the tools you already use and connect systems that don't talk to each other.

· Integration via API, Zapier, or GAS
· Connect accounting software, PMS, and spreadsheets
· Eliminate double entry and re-keying
· Phased rollout without disrupting current work

How It Works

We don't start big. We start small, prove the value, and take it all the way to production.

Discovery & Requirements

We map your workflow, data, and goals into something AI can actually solve.

Free · online OK

PoC / Prototype

We build small first and validate value and feasibility on real data.

From ~2 weeks

Build

We build the production version and roll it out without stopping your work.

Integrates with your tools

Operate & Improve

We keep supporting it after launch — improvements and new features.

Monthly support

Example Use Cases

Works best where there's repetitive work or not enough hands. These are representative examples.

Inquiry triage agent

AI handles first response across email/chat/LINE; only complex cases reach staff.

Quote & document drafting

AI drafts quotes and reports from your templates and past data.

Internal knowledge search

A RAG app that searches manuals, policies, and past projects and answers with sources.

Data sync

Booking, inventory, and customer data synced across tools — no double entry.

Custom dashboards

Sales, occupancy, and KPIs aggregated automatically and shown in real time.

Document OCR → system

Receipts, invoices, and forms read by AI and pushed into your core system.

These are illustrative examples. We design around your actual workflow.

Why Benstay?

✓

Finance-grade engineering
Our founder spent 11 years in technology at Goldman Sachs in Tokyo — large-scale systems and automation, applied to SMB-sized projects.

✓

We build & run our own
Reshito (AI receipt-scanning SaaS), Tokira (booking SaaS), a multilingual AI chatbot, and 30+ in-house tools. We don't just resell.

✓

End-to-end, in-house
Requirements, build, deployment, and ongoing improvement are all handled in-house. No outsourced telephone game.

✓

Bilingual, Japan-based
Work with us in English while we handle the Japanese side — vendors, data, and users — on the ground.

How Pricing Works

The right approach depends on what you're building, so the first consultation and estimate are free.

Start here

Free consult & estimate

We learn your goal and what you want built, then propose an approach and a quote.

Spot development

Quoted per project

PoCs, prototypes, and one-off builds are quoted to scope and requirements.

Ongoing

From ¥50,000/mo

Continuous development, operation, improvement, and new features.

We recommend starting small, confirming the value, then expanding in stages.

Frequently Asked Questions

What can you build?

Custom AI agents, generative-AI/LLM apps (chat, document generation, summarization, classification), business systems and internal tools, and AI added to your existing systems. We design and build to your requirements.

How much does it cost?

It depends on scope. The initial consultation and estimate are free. We offer one-off (spot) development and an ongoing development & operation plan from ¥50,000/month.

How long does it take?

We start with a PoC or prototype, typically from about two weeks, then move to full build once the value is confirmed. We start small and expand in stages.

Can you connect ChatGPT or other LLMs to our own data?

Yes. We build retrieval-augmented (RAG) setups that answer based on your documents and data, and embed generative AI into your existing tools and sites.

Do you support the product after delivery?

Yes. We continue with operation, improvement, and new features after delivery (monthly plan), so it keeps working in practice.

Do you work in English?

Yes. Our team is bilingual (Japanese and English), so overseas founders and non-Japanese-speaking owners can work with us directly while we handle the Japanese side.

Free AI Development Consultation

Even a "could you build this?" question is fine.
We'll get back to you within one business day.

Custom AI Agents & AI/DX Developmentfor Businesses in Japan