Upload File (Merchant Attachment)

Uploads a document to a merchant application as a Base64-encoded attachment. Each upload must specify the attachment type, which categorizes the document within the underwriting and compliance workflow. Supported types cover a wide range of documents including void checks, bank statements, driver's licenses, processing statements, tax returns, PCI certificates, MPA confirmations, and more.

Endpoint

POST /api/v1/merchant/attachment

Authentication

Basic HTTP Authentication required.
Encode username:password in Base64 and pass in the Authorization header:

Authorization: Basic {base64(username:password)}

When to use

Call this endpoint whenever an underwriter requests supporting documentation, or when proactively submitting documents as part of the boarding workflow. Documents uploaded here are visible to underwriters in the merchant's application record. Upload a voided check or bank account proof before advancing to underwriting review, and upload the driver's license or other ID document for all owners with 25% or greater ownership.

Request Body

Supported attachmentType values:

{
  "id": 10482,
  "attachmentType": "VoidCheck",
  "data": "JVBERi0xLjQKJdPr6eEKMSAwIG9iago8PAovQ3JlYXRpb25EYXRlKEQ6MjAyNjA1...",
  "fileName": "voided_check_green_tree_cafe.pdf",
  "comment": "Voided check for Bank of America account ending in 9012.",
  "riskDocument": false
}

Response

200 OK

{
  "data": {
    "success": true
  },
  "status": "OK",
  "error": null,
  "warning": null,
  "validationResults": [],
  "requestId": 92018
}

Error Codes

Common Mistakes

• Sending raw binary file content instead of Base64-encoded content — the data field must be a Base64 string.
• Omitting the file extension in fileName — underwriters rely on the file name to identify document type.
• Using an attachmentType value not in the allowed enum (e.g., "BankStatements" instead of "BusinessBankStatements") returns a 400 validation error.
• Uploading very large files (e.g., multi-page scanned PDFs) without compressing them first — reduce file size to avoid 413 errors.
• Not including a comment when uploading a document in response to an underwriting note — always reference the note so the underwriter knows which item is addressed.

Related Endpoints

• GET /api/v1/merchant/underwritingNotes — Retrieve underwriting notes that identify which documents are needed.
• POST /api/v1/merchant/underwritingPending — Set the application to "Pending" after uploading requested documents.
• POST /api/v1/merchant/underwritingReview — Advance to "Pending Review" once all documents are uploaded.

Example

curl -X POST https://hq.staging.netevia.dev/api/v1/merchant/attachment \
  -H "Authorization: Basic $(echo -n 'username:password' | base64)" \
  -H "Content-Type: application/json" \
  -d '{
    "id": 10482,
    "attachmentType": "VoidCheck",
    "data": "'"$(base64 -w 0 voided_check.pdf)"'",
    "fileName": "voided_check_green_tree_cafe.pdf",
    "comment": "Voided check for Bank of America account ending in 9012.",
    "riskDocument": false
  }'