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An upload is a file stored in SignatureAPI. You can use an upload as the source file for a document in an envelope. Uploads are the simplest way to supply document files when you do not want to host them yourself. After uploading a file, pass the returned url value as the url property of a document. The following file formats are supported:
FormatMedia Type
PDFapplication/pdf
DOCXapplication/vnd.openxmlformats-officedocument.wordprocessingml.document

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Retention

Uploads have one of two retention types, indicated by the retention property:
RetentionDescription
TemporaryCreated through the API. Automatically deleted 24 hours after creation. Use this for one-time document sends.
PermanentCreated through the Library in your dashboard. Stored indefinitely and reusable across multiple envelopes. Identified by a unique key.
The Upload resource replaces the File resource. The File resource is soft-deprecated but remains available for backward compatibility.

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Attributes

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id
string
required
The unique identifier of the upload.
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retention
enum
required
The retention type of the upload.
ValueDescription
temporaryThe file is automatically deleted 24 hours after creation.
permanentThe file is stored indefinitely. Created through the dashboard library.
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key
string
A unique identifier for the upload within your account. Present only on permanent uploads (retention is permanent).Only lowercase letters, numbers, hyphens, and underscores are allowed. Maximum 100 characters.
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url
string
required
The internal URL used to reference this upload in other API calls, such as document.url.You cannot use this URL to download the file directly.
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format
enum
required
The file format of the upload.
ValueDescription
pdfA PDF file (application/pdf).
docxA DOCX file (application/vnd.openxmlformats-officedocument.wordprocessingml.document).
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sha_256
string
required
The SHA-256 hash of the uploaded file, in hexadecimal format.
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size
integer
required
The size of the uploaded file in bytes. Maximum 5 MB (5,242,880 bytes).
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created_at
string
required
The date and time when the upload was created, in ISO 8601 format.
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expires_at
string
The date and time when the upload will be automatically deleted, in ISO 8601 format. Present only on temporary uploads (retention is temporary). The expiration is 24 hours after creation.
// HTTP Status Code 200

{
  "id": "upl_1sAAaVfabdt0esVjmSTmLA",
  "retention": "temporary",
  "url": "https://api.signatureapi.com/v1/uploads/upl_1sAAaVfabdt0esVjmSTmLA",
  "format": "pdf",
  "sha_256": "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
  "size": 102400,
  "created_at": "2025-12-30T12:00:00.000Z",
  "expires_at": "2025-12-31T12:00:00.000Z"
}