RegBase Public API

Free JSON API for Japanese company
and enforcement records.

A lightweight, no-signup API for developers, AI builders, and small compliance tools. The free tier is limited to 10 requests per 60 seconds.

Open sample API OpenAPI JSON Search in browser

Quick start

Get your first JSON response in 30 seconds

Start with `GET /api/v1/search`. It returns company profiles and enforcement records together, which makes it the simplest entry point for AI workflows and internal tools.

https://regbase.jp/api/v1/search?q=Toyota&limit=5

Open JSON

For AI agents

Optimized for LLMs and Custom GPT Actions

RegBase publishes an OpenAPI schema and llms.txt guide for AI agents, Custom GPT Actions, RAG pipelines, and internal compliance workflows. Start by importing the OpenAPI schema.

https://regbase.jp/api/openapi.json https://regbase.jp/llms.txt

Endpoints

GET/api/v1/search?q={query}

Searches company profiles and enforcement records in one request. The combined response is capped at 10 records.

GET/api/v1/companies?q={query}

Searches Japanese companies by Japanese name, English name, or Corporate Number. `q` is required. `limit` accepts values from 1 to 10.

GET/api/v1/enforcements?company={name}

Returns public enforcement records. Supports `company` / `q` / `corporate_number` / `law` / `authority` / `action_type` / `limit`. At least one filter is required.

curl

curl "https://regbase.jp/api/v1/search?q=Toyota&limit=5" \
  -H "X-RegBase-Client: your-app-name" \
  -H "X-RegBase-Contact: dev@example.com"

`X-RegBase-Client` is optional, but it helps us understand who is building on top of RegBase. `X-RegBase-Contact` is also optional. No API key or account is required.

JavaScript example

const res = await fetch("https://regbase.jp/api/v1/search?q=Toyota&limit=5", {
  headers: {
    "X-RegBase-Client": "your-app-name",
    "X-RegBase-Contact": "dev@example.com"
  }
});

const json = await res.json();
console.log(json.data.companies, json.data.enforcements);

Minute Limit

10/min

Requests are grouped by IP, User-Agent, and optional client name.

Daily Limit

300/day

Rolling 24-hour limit per anonymous client.

Max Limit

10 rows

No bulk listing, empty search export, offset, or cursor.

Data protection and abuse controls

Anonymous clients are limited to 10 requests per minute and 300 requests per rolling 24 hours.
`/api/v1/companies` requires `q`; `/api/v1/enforcements` requires at least one filter.
`limit` is capped at 10 rows. There is no full-dataset pagination with `offset` or `cursor`.
High-volume distinct searches or sequential Corporate Number scans return `429 automated_enumeration_detected`.