anchor.diff:  |sandbox|boolean|Whether or not to use the sandbox sending domain ( **Note:** SparkPost only )| no |Defaults to false. |
   |skip_suppression|boolean|Whether or not to ignore customer suppression rules, for this transmission only.  Only applicable if your configuration supports this parameter. ( **Note:** SparkPost Elite only )| no - Defaults to false |  Unlike most other options, this flag is omitted on a GET transmission response unless the flag's value is true. |
   
  -
  +### Inline Content Attributes
  +
  +The following attributes are used when specifying inline content in the transmission's "content" JSON object. Note that these attributes should not be present if using a stored template.
  +
  +| Field         | Type     | Description                           | Required   | Notes   |
  +|------------------------|:-:       |---------------------------------------|-------------|--------|
  +|html    |string  |HTML content for the email's text/html MIME part|At a minimum, html or text is required.  |Expected in the UTF-8 charset with no Content-Transfer-Encoding applied.  Substitution syntax is supported. |
  +|text    |string  |Text content for the email's text/plain MIME part|At a minimum, html or text is required. |Expected in the UTF-8 charset with no Content-Transfer-Encoding applied.  Substitution syntax is supported.|
  +|subject |string  |Email subject line   | yes |Expected in the UTF-8 charset without RFC2047 encoding.  Substitution syntax is supported. |
  +|from |string or JSON  | Address _"from" : "deals@company.com"_ or JSON object composed of the "name" and "email" fields _"from" : { "name" : "My Company", "email" : "deals@company.com" }_ used to compose the email's "From" header| yes | Substitution syntax is supported. |
  +|reply_to |string  |Email address used to compose the email's "Reply-To" header | no | Substitution syntax is supported. |
  +|headers| JSON | JSON dictionary containing headers other than "Subject", "From", "To", and "Reply-To"  | no |See the Header Notes. |
  +|attachments| JSON | JSON array of attachments ( **Note:** SparkPost Elite only ) | no | For a full description, see Attachment Attributes. |
  +|images| JSON | JSON array of inline images ( **Note:** SparkPost Elite only ) | no | For a full description, see Image Attributes. |
  +
  +#### Header Notes
  +
  +* Headers such as "Content-Type" and "Content-Transfer-Encoding" are not allowed here as these are auto generated upon construction of the email.
  +* The "To" header should not be specified here, since it is generated from each recipient's _address.name_ and _address.email_.
  +* Each header value is expected in the UTF-8 charset without RFC2047 encoding.
  +* Substitution syntax is supported.
  +
  +#### email_rfc822 Notes
  +
  +Alternately, the content JSON object may contain a single "email_rfc822" field.  email_rfc822 is mutually exclusive with all of the above fields.
  +
  +| Field         | Type     | Description                           | Required   | Notes   |
  +|--------------------|:-:       |---------------------------------------|-----------------------|--------|
  +|email_rfc822    |string  |Pre-built message with the format as described by the [message/rfc822 Content-Type](http://tools.ietf.org/html/rfc2046#section-5.2.1) |no   |  See the email_rfc822 Notes. |
  +
  +* Substitutions will be applied in the top-level headers and the first non-attachment text/plain and
  +first non-attachment text/html MIME parts only.
  +* Lone `LF`s and lone `CR`s are allowed. The system will convert line endings to `CRLF` where
  +necessary.
  +* The provided email_rfc822 should NOT be dot stuff.  The system dot stuffs before sending the outgoing message.
  +* The provided email_rfc822 should NOT contain the SMTP terminator `\r\n.\r\n`.  The system always adds this terminator.
  +* The provided email_rfc822 in MIME format will be rejected if SparkPost and SparkPost Elite cannot parse the contents into a MIME tree.
  +
  +### Attachment Attributes
  +
  +**Note:** SparkPost Elite only
  +
  +Attachments for a transmission are specified in the content.attachments JSON array where each JSON object in the array is described by the following fields:
  +
  +| Field         | Type     | Description                           | Required   | Notes   |
  +|--------------------|:-:       |---------------------------------------|-------------|------------------|
  +|type |string |The MIME type of the attachment. E.g. "text/plain", " image/jpeg", "audio/mp3", "video/mp4", "application/msword", "application/pdf", etc, including the "charset" part if needed, e.g. '"text/html; charset="UTF-8"' The value will apply "as-is" to the "Content-Type" header of the generated MIME part for the attachment. | yes |  |
  +|name |string |The filename of the attachment (for example, "document.pdf"). This is inserted into the Content-Type and Content-Disposition headers. | yes | Maximum length - 255 bytes |
  +|content |string |The content of the attachment as a Base64 encoded string. | yes | |
  +
  +### Image Attributes
  +
  +**Note:** SparkPost Elite only
  +
  +Inline images for a transmission are specified in the content.images JSON array where each JSON object in the array is described by the following fields:
  +
  +| Field         | Type     | Description                           | Required   | Notes   |
  +|--------------------|:-:       |---------------------------------------|-------------|------------------|
  +|type |string |The MIME type of the image.  E.g. "image/jpeg".  The value will apply "as-is" to the "Content-Type" header of the generated MIME part for the image. | yes |  |
  +|name |string |The name of the inline image, which will be inserted into Content-Type, Content-Disposition and Content-ID headers. The image should be referenced in your HTML content using \<img src="cid:THIS_NAME"\>. The name must be unique within the content.images array. | yes | Maximum length - 255 bytes |
  +|content |string | The content of the image as a Base64 encoded string. | yes | |
   
   ### Using a Stored Template
   
  -The following content attributes are used when specifying a stored template in the transmission. Note that these attributes should not be present when using inline templates.
  +The following attributes are used when specifying a stored template in the transmission's "content" JSON object. Note that these attributes should not be present when using inline content.
   
   | Field         | Type     | Description                           | Required   | Notes   |
   |------------------------|:-:       |---------------------------------------|-------------|--------|
  
positive.code:         {
            "results": {
              "id": "another_summer_sale"
            }
          }
  
  + Request Create with attachments (application/json)
  
    + Headers
  
              Authorization: 14ac5499cfdd2bb2859e4476d2e5b1d2bad079bf
  
    + Body
  
          ```js
          {
            "id" : "attachment_example_sparkpost_elite_only",
            "content": {
              "from": {
                "email": "billing@company.example",
                "name": "Example Company"
              },
  
              "subject": "Billing statement",
              "html": "<b>Please see your attached billing statement</b>",
              "attachments" : [
                {
                  "type" : "application/pdf",
                  "name" : "billing.pdf",
                  "content" : "Q29uZ3JhdHVsYXRpb25zLCB5b3UgY2FuIGJhc2U2NCBkZWNvZGUh"
                },
                {
                  "type" : "text/plain; charset=UTF-8",
                  "name" : "explanation.txt",
                  "content" : "TW92ZSBhbG9uZy4gIE5vdGhpbmcgdG8gc2VlIGhlcmUu"
                }
              ]
            }
          }
          ```
  
  + Response 200 (application/json)
  
          {
            "results": {
              "id": "attachment_example_sparkpost_elite_only"
            }
          }
  
  + Request Create with inline images (application/json)
  
    + Headers
  
              Authorization: 14ac5499cfdd2bb2859e4476d2e5b1d2bad079bf
  
    + Body
  
          ```js
          {
            "id" : "inline_image_example_sparkpost_elite_only",
            "content": {
              "from": {
                "email": "marketing@company.example",
                "name": "Example Company"
              },
  
              "subject": "Inline image example",
              "html": "<html><body>Here is your inline image!<br> <img src=\"cid:my_image.jpeg\"></body></html>",
              "images" : [
                {
                  "type" : "image/jpeg",
                  "name" : "my_image.jpeg",
                  "content" : "VGhpcyBkb2Vzbid0IGxvb2sgbGlrZSBhIGpwZWcgdG8gbWUh"
                }
              ]
            }
          }
          ```
  
  + Response 200 (application/json)
  
          {
            "results": {
              "id": "inline_image_example_sparkpost_elite_only"
            }
          }
  
  
negative.code: |from |string or JSON  | Address _"from" : "deals@company.com"_ or JSON object composed of the "name" and "email" fields _"from" : { "name" : "My Company", "email" : "deals@company.com" }_ used to compose the email's "From" header| yes | Substitution syntax is supported. |
  |reply_to |string  |Email address used to compose the email's "Reply-To" header | no | Substitution syntax is supported. |
  |headers| JSON | JSON dictionary containing headers other than "Subject", "From", "To", and "Reply-To"  | no |See the Header Notes. |
  
  #### Header Notes
  
  