NTA Corporate Number Web API (houjin-bangou.nta.go.jp)

API overview

The National Tax Agency of Japan (NTA, 国税庁) operates the Corporate Number System (法人番号システム), which assigns a unique 13-digit corporate number to every legal entity in Japan. The Web API at api.houjin-bangou.nta.go.jp exposes this registry to registered developers at no cost.

The system covers approximately 6.8 million legal entities: kabushiki kaisha (KK, joint-stock companies), godo kaisha (GK, limited liability companies), incorporated associations and foundations, and government bodies. The registry publishes: the 13-digit corporate number (houji-bangou), the official Japanese-script company name, the registered address in Japanese script, entity type, date of incorporation, and current status.

Critical limitation: the NTA Corporate Number API exposes only the registry portion of company data. It does not expose directors, shareholders, beneficial owners, financial statements, or court records. For those data layers you need to query the Ministry of Justice Legal Affairs Bureau (Houmu Kyoku) portal separately, which is not available via a developer API. The NTA API is effectively a name-and-address lookup system with national coverage, not a full company intelligence API.

Endpoint reference

Base URL: https://api.houjin-bangou.nta.go.jp/4

The current version is v4 (path segment /4/).

Key query parameters for /num:

• id: your API key
• number: corporate number(s), comma-separated, up to 10 per request
• type: response format: 01 (XML), 02 (JSON), 12 (CSV)
• history: 0 (latest only) or 1 (all historical records)

Key query parameters for /name:

• name: company name string (Japanese or transliteration)
• mode: 1 (forward match) or 2 (partial match)
• target: 1 (name + kana) or 2 (name only)
• change: include name changes: 0 (no), 1 (yes)

Authentication

Authentication uses a query parameter: id=YOUR_API_KEY. There is no header-based auth.

Registration process:

1. Navigate to houjin-bangou.nta.go.jp/webapi/
2. Click the application form link (Japanese-language page)
3. Complete the registration form with your name, organisation, email address, and intended use. The form is in Japanese; browser translation is workable.
4. Submit. An API key is typically issued within 1-3 business days via email.

There is no fee. API keys do not have a documented expiry. The NTA terms of use require you to identify your application and prohibit redistribution of the raw data as a standalone product. The key is personal to the registered account; do not share it or expose it in client-side code.

Rate limits and quotas

The NTA does not publish explicit rate limits for the Corporate Number Web API. The service is sized for developer use, not high-frequency production scraping.

Observed behaviour: requests complete in 200-800ms. Sustained rates above 5 requests per second from a single IP have produced HTTP 503 responses in tests. The name search endpoint (/name) is slower than the number lookup (/num) under load.

For bulk workloads, use the /download endpoint to retrieve the full corporate number database as a CSV file (available in parts). The download file is updated monthly and is the correct tool for populating a local search index of Japanese company names and numbers.

The /diff endpoint provides daily change files showing new registrations, name changes, and status updates. Polling /diff daily is far more efficient than polling /num for individual companies to detect changes.

Sample request

# Lookup by corporate number (returns JSON)
curl "https://api.houjin-bangou.nta.go.jp/4/num?id=YOUR_API_KEY&number=1234567890123&type=02"

# Name search (partial match, JSON)
curl "https://api.houjin-bangou.nta.go.jp/4/name?id=YOUR_API_KEY&name=%E3%83%88%E3%83%A8%E3%82%BF&mode=2&type=02"

URL-encode Japanese characters. The name parameter expects UTF-8 percent-encoded Japanese text. The example above encodes “トヨタ” (Toyota in katakana).

Sample response

{
  "lastUpdateDate": "2026-05-16",
  "count": 1,
  "divideNumber": 1,
  "divideSize": 1,
  "corporations": [
    {
      "sequenceNumber": "1",
      "corporateNumber": "1234567890123",
      "process": "01",
      "correct": "0",
      "updateDate": "2024-03-15",
      "changeDate": "2024-03-15",
      "name": "サンプル株式会社",
      "nameImageId": null,
      "kind": "301",
      "prefectureName": "東京都",
      "cityName": "千代田区",
      "streetNumber": "丸の内1-1-1",
      "addressImageId": null,
      "prefectureCode": "13",
      "cityCode": "101",
      "postCode": "1000005",
      "addressOutside": null,
      "closeDate": null,
      "closeCause": null
    }
  ]
}

kind field values: 101 = national government, 201 = local government, 301 = KK (kabushiki kaisha), 302 = LLC/GK, 303 = foundation, 304 = NPO. closeDate and closeCause populate when the entity has been dissolved.

Available data fields

• 13-digit corporate number
• Official company name (Japanese script)
• Name image ID (link to official name image, for entities with characters not in the standard character set)
• Entity type code
• Prefecture and city of registered address
• Street address (Japanese format, not geocoded)
• Post code
• Address outside Japan (for foreign-registered entities)
• Last update date, change date
• Close date and close cause (dissolution reason code)
• Process type (registration, update, close)

Known limitations and edge cases

Japanese-script only. All name and address fields are in Japanese. There is no Romanised (romaji) output. If your application targets English-speaking users, you must either transliterate programmatically or maintain a separate mapping. The /name search accepts romaji input but match quality degrades significantly; Japanese-script input returns far better results.

No directors or shareholders. The NTA registry covers legal existence and address only. Director names, shareholding, and beneficial ownership require a separate query to the Ministry of Justice Legal Affairs Bureau (Houmu Kyoku) register, which is accessible via a web portal but does not have a public developer API as of May 2026.

Entity kind 301 ambiguity. The kind code 301 covers all kabushiki kaisha regardless of size. There is no distinction between publicly listed KKs and small private KKs in this field.

Page count limits on name search. The /name endpoint returns a maximum of 2,000 results. For generic terms, the result set is capped and may not include all matches. Use more specific name strings or the /download bulk file for exhaustive lookups.

Character encoding edge cases. Some older company registrations include kanji characters outside the standard Unicode BMP. The nameImageId field provides a reference to an official image of the name when the text cannot be rendered in standard Unicode. Your pipeline must handle null text fields for these records.

Commercial alternatives

The NTA API covers name, address, and status for all Japanese legal entities at no cost, which is a strong starting point. It cannot replace a full company intelligence pull.

For directors, shareholding history, financial statements (yukashoken hokokusho), and credit data, developers typically use: Teikoku Databank (TDB) API, Tokyo Shoko Research (TSR) API, or international aggregators like Bureau van Dijk Orbis. These services are priced in JPY (typically JPY 1,500 to JPY 15,000 per detailed report, roughly USD 10 to USD 100) and require Japanese corporate accounts or partnership agreements for API access. See the corresponding Japan company registry guide for the full registry landscape.

Last verified: 2026-05-17. The NTA Corporate Number Web API is a live government service. Verify current version and endpoints at houjin-bangou.nta.go.jp/webapi/ before production deployment.