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What you can issue

Issue National Tax Service certificates from Hometax and download the original PDF. Issuance does not finish within the request. Retrieve the result with the issuanceKey from the accepted response.

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Requirements

  • You can issue documents only for the business that owns the API key.
  • Register a joint certificate in the Bolta dashboard.
  • Each document deducts 500 points. A failed issuance deducts nothing.

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Supported documents

  • Business registration certificate reissue: Bolta prints reason as is on the certificate. Enter the actual reason, for example 분실 (lost). The API trims leading and trailing spaces. It returns 400 INVALID_REQUEST if the reason is empty, longer than 10 characters, or contains control characters.
  • English business registration proof: Bolta issues it with the English business information registered in Hometax. If that information is missing or malformed, the request ends as FAILED and deducts no points. To change the English details, update them in Hometax first.
  • Tax payment certificate: Hometax does not issue it while national taxes are in arrears. The emigration purpose is not supported. The certificate is valid for 30 days from the issue date.
  • VAT tax base proof: Set from to January or July and to to June or December. from cannot be later than to; otherwise the API returns 400 INVALID_REQUEST. One request covers up to five years.
  • Standard financial statement proof: For a corporation with a December year end, enter 2025-12 for fiscal year 2025. For a sole proprietor, only the year is used. Only fiscal years with a filed corporate or comprehensive income tax return can be issued.

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Request a document

Set a new Bolta-Client-Reference-Id (1 to 255 characters) for each request. If you did not receive a response, resend the same value and body. The API returns the existing request. The API returns 202 Accepted with the response below.
The response language is the language of the issued document. It is always KO for documents other than the business registration proof.

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Retrieve the result

Issuance usually finishes within 30 seconds. Poll every 5 to 10 seconds. Bolta processes one request at a time for each business. If you send several at once, each request starts after the previous one finishes. A COMPLETED response fills in these fields. When the URL expires, retrieve the result again to get a new one. After the retention period, downloadUrl is null. The downloaded file is named {document name}_{business registration number}_{issue date}.pdf with the Korean document name, for example 사업자등록증명_123-45-67890_20260919.pdf. An English proof starts with 사업자등록증명(영문)_.... Clients that do not support UTF-8 file names get an ASCII name such as business-registration-proof_1234567890_20260919.pdf. The same document downloaded more than once on the same day gets the same file name, so store the file together with its issuanceKey.

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Test key

Test keys do not submit to Hometax and deduct no points. They accept only the business registration numbers below. For 1000000014, the COMPLETED result includes a sample PDF URL. The sample is not a real document and has the same content for every document type. Its issue date is fixed at January 1, 2026. The URL lifetime (5 minutes), retrieving again after expiry, and the file naming rule work the same as live issuance, so use a test key to check your download integration.

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Errors