Attachments

Upload files to AgentSend and attach them to outgoing messages. Retrieve presigned URLs to download or share attachment content.

💡

Upload an attachment first, then reference its id in the attachmentIds field when sending a message. Attachments are stored securely and accessible via time-limited presigned URLs.

Upload Attachment

POST /attachments

Uploads a file and returns an Attachment object. Use the returned id to attach the file to a message. The request must use multipart/form-data encoding.

Request Body

Content-Type: multipart/form-data

Field	Type	Description
`file` obrigatório	file	The file to upload. The filename and content type are inferred from the uploaded part.

Example Request

bash

curl -X POST https://api.agentsend.io/attachments \
  -H "x-api-key: $AGENTSEND_API_KEY" \
  -F "file=@/path/to/report.pdf"

javascript

const form = new FormData();
form.append("file", fileBlob, "report.pdf");

const res = await fetch("https://api.agentsend.io/attachments", {
  method: "POST",
  headers: { "x-api-key": process.env.AGENTSEND_API_KEY },
  body: form,
});

const attachment = await res.json();
console.log(attachment.id); // use this id when sending a message

Response — 201 Created

json

{
  "id": "att_01j9zxkp4qbc7n3m8td5e6fvg2",
  "filename": "report.pdf",
  "contentType": "application/pdf",
  "size": 204800,
  "url": "https://storage.agentsend.io/att_01j9zxkp4qbc7n3m8td5e6fvg2/report.pdf?token=...",
  "createdAt": "2025-11-10T08:15:00Z"
}

Get Attachment

GET /attachments/{id}

Retrieves metadata and a short-lived presigned download URL for an attachment. Use the url field to download or display the file content directly.

Path Parameters

Parameter	Type	Description
`id` obrigatório	uuid	The ID of the attachment to retrieve.

Example Request

bash

curl https://api.agentsend.io/attachments/att_01j9zxkp4qbc7n3m8td5e6fvg2 \
  -H "x-api-key: $AGENTSEND_API_KEY"

Response — 200 OK

json

{
  "id": "att_01j9zxkp4qbc7n3m8td5e6fvg2",
  "filename": "report.pdf",
  "contentType": "application/pdf",
  "size": 204800,
  "url": "https://storage.agentsend.io/att_01j9zxkp4qbc7n3m8td5e6fvg2/report.pdf?token=...",
  "createdAt": "2025-11-10T08:15:00Z"
}

Attachment Object

Field	Type	Description
`id`	string	Unique identifier for the attachment.
`filename`	string	Original filename as provided at upload time.
`contentType`	string	MIME type of the file (e.g. `application/pdf`, `image/png`).
`size`	number	File size in bytes.
`url`	string	Presigned URL to download the file. This URL is time-limited; fetch a fresh one by calling this endpoint again if it expires.
`createdAt`	string	ISO 8601 timestamp when the attachment was uploaded.

ℹ

Presigned URLs expire after a short period. If you need to share or re-download an attachment, call GET /attachments/{id} again to obtain a fresh URL.

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