BILL enables you to upload supporting attachments for vendors, customers, and invoices. In addition, you can upload documents for bills. See [Invoice PDF email attachments](doc:ar-invoice-pdf-email-attachments) to learn about adding and replacing invoice PDF attachments. > 👍 All attachments API operations are similar > > The vendor attachment, customer attachment and invoice attachmen API operations are similar. In this section, the vendor attachment example is explained. See the /v3/attachments API for more information. ## Upload a vendor attachment In your `POST /v3/attachments/vendors/{vendorId}` request, set the required fields. | Field | Description | | :--------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `vendorId` | BILL-generated ID of the vendor. The value begins with **`009`**. | | `name` | File name with extension. For example, to upload a PDF attachment titled **`business_details`**, set **`name`** as **`business_details.pdf`**. | | `file` | Attachment file. The file size limit is 6 MB. See Supported file formats in the BILL Help Center for more information. | ### Sample request In this cURL example, an attachment file is uploaded for a vendor. ```curl curl --request POST \ --url '{baseUrl}/connect/v3/attachments/vendors/{vendorId}?name={file_name}' \ --header 'devKey: {developer_key}' \ --header 'sessionId: {session_id}' \ --header 'accept: application/json' \ --header 'content-type: */*' \ --data-binary '@{filepath}' ``` ### Response In the response, an attachment `id` is available. The value begins with `att`. In addition, `downloadLink` is the generated URL for downloading the attachment. Use the URL in a GET request to download the attachment. ```json { "id":"{attachment_id}", "name":"{file_name}", "createdTime":"2026-12-16T23:19:20.000+00:00", "downloadLink":"{baseUrl}/AttachDownload?id={attachment_id}" } ``` > ❗️ BILL takes a few minutes to complete the upload process > > When you upload an attachment, it takes a few minutes for BILL to complete the upload process and to generate a preview of the attachment. The download process will be successful only after the upload process is complete. ### Download an attachment In this cURL example, an attachment is downloaded. In the request, `downloadLink` is set from the upload attachment response. ```curl curl '{downloadLink}' \ --header 'sessionId={session_id}' \ --output {attachment_name} ``` See the /v3/attachments API for more information. ## Upload a bill document In your `POST /v3/documents/bills/{billId}` request, set the required fields. | Field | Description | | :------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `billId` | BILL-generated ID of the bill. The value begins with **`00n`**. | | `name` | File name with extension. For example, to upload a PDF attachment titled **`business_details`**, set **`name`** as **`business_details.pdf`**. | | `file` | Document file. The file size limit is 6 MB. See Supported file formats in the BILL Help Center for more information. | ### Sample request In this cURL example, an document file is uploaded for a bill. ```curl curl --request POST \ --url '{baseUrl}/connect/v3/documents/bills/{billId}?name={file_name}' \ --header 'devKey: {developer_key}' \ --header 'sessionId: {session_id}' \ --header 'accept: application/json' \ --header 'content-type: */*' \ --data-binary '@{filepath}' ``` ### Response In the response, a document `uploadId` is available. The value begins with `0du`. This is a temporary BILL-generated ID for the document when the upload is in progress. When the upload is complete, a new BILL-generated ID is available for the document. The value begins with `00h`. You can get the document upload status with `GET /v3/documents/upload-status`. ```json { "uploadId":"{document_upload_id}" } ``` See the /v3/documents API for more information.