v1

latestSwagger 2.02026-07-13151175.7 KB

Attachments

Upload an attachment via a signed URL

When composing an SMS, you can add SMS attachments by adding a URL to your text. When the recipient clicks on the URL, the attached file will be downloaded and opened on their mobile device.

The best way to do this is to store the file on a web server you own and use that URL in the SMS text. This URL will be easily recognisable to your message recipient and ties your message back to your brand or company.

If that’s not possible, you can use BulkSMS storage to keep the files that you want to attach to your SMS. These files will be deleted after 30 days as per our fair use policy.

We recommend you keep this file size below 20 MB, as larger files may be deleted without warning.

To use the BulkSMS storage, follow these three steps:

Step 1: Use your BulkSMS credentials (or your API Token) to request a pre-signed URL. This is what this pre-sign-attachment method is for. It returns a PreSignInfo object that you will use in the other two steps.

Step 2: Upload the file using a standard HTTP PUT request. For your PUT request, use the value of putURL from the PreSignInfo object as the request address. You also have to add the entries from the fields property (of the PreSignInfo object) to the headers of your 'PUT' request. You send the file content as the body of the PUT request.

Step 3: Now you can use the value of fetchURL from the PreSignInfo object in the body of your SMS messages and send those using the usual messaging API (described elsewhere in this document). If you send the same file to many recipients, it is safe to use the same URL for all of them.

If you need to, take a closer look at the example program (on the right-hand side) to get a better idea of how to implement this process.

post/rmm/pre-sign-attachment

Request body

fileExtensionstring

The extension of the file. Usually related to the media type.

mediaTypestring

The media type of the file you would like to upload. If you are not sure what value to use here, check out the standard list of media types.

Example request

{
  "fileExtension": "pdf",
  "mediaType": "application/pdf"
}

Response

A PreSignInfo object

putUrlstring

The address of the PUT request to upload the file.

fetchUrlstring

The URL you use in your SMS text. It is the file location.

Example response

{
  "putUrl": "https://some.place/aethzd.pdf?Token=IQoJb3JpZ2luX2EP3",
  "fetchUrl": "https://smsattach.it/bedhkd.pdf",
  "fields": [
    {
      "name": "x-amz-acl",
      "value": "public-read"
    }
  ]
}