Upload a file

Files upload straight to storage through a short-lived signed URL, then you register them with Heliyos. The upload itself never carries your API key.

Get an upload URL

curl https://api-prod.heliyos.ai/v1/platform/attachments/presigned-urls \
  -H "Authorization: Bearer $HELIYOS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "fileName": "pricing-2026.pdf",
    "mimeType": "application/pdf",
    "objectType": "company",
    "fileSize": 482113
  }'

The answer has presignedUrl (valid for one hour) and fileKey. The allowed file types and the 25 MB size limit are on Create an upload URL.

Upload the bytes

PUT the file to presignedUrl with the same Content-Type and size you declared. Do not send your API key on this request.

curl -X PUT "$PRESIGNED_URL" \
  -H "Content-Type: application/pdf" \
  --data-binary @pricing-2026.pdf

Create the file record with the fileKey from step 1, and link it to a record:

curl https://api-prod.heliyos.ai/v1/platform/attachments \
  -H "Authorization: Bearer $HELIYOS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "fileName": "pricing-2026.pdf",
    "fileSize": 482113,
    "mimeType": "application/pdf",
    "storageKey": "<fileKey>",
    "storageProvider": "S3",
    "url": "<presignedUrl without its query string>",
    "relationships": [
      {
        "objectId": "<company id>",
        "schemaId": "<companies object id>",
        "objectType": "company"
      }
    ]
  }'

The exact fields, including how to add the file to the knowledge base instead, are on Create a file.

To let someone download it later, call Get a file download link. The link expires after 60 seconds, so fetch it right before you use it.

The MCP tool heliyos_files_upload does all three steps for you.

Last modified on November 5, 2026

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