> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mapp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Send a transactional message

> Sends a prepared message as a transactional message, and adds user as member to group the prepared message belong to. <br> Please be aware this may cause that user to be unexpectedly subscribed or re-subscribed to that group. <br>Attachments may be added as part of the JSON payload. If you wish to attach a file to the message, the data must be Base64 encoded <br>and added as the value of the attachment’s content string, as demonstrated below. Request body example with attachment: <br><br><pre>{<br>"parameters":<br>  [{"name" : "Parameter Name 1","value" : "Parameter Value 1"},<br>   {"name" : "Parameter Name 2","value": "Parameter Value 2"}],<br>    "attachments":<br>    [{"name" : "twitter_logo.png",<br>      "contentType" : "image/png",<br>      "content": "iVBORw0KGgoAAAANSUhEUgAAABUAAAARCAYAAAAyhueAAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAASFJREFUeNqslM0NgkAQhRdiAdiAgQ6468EO1INntQOpwFABdqBe9aAdiIl3twS1AbECfJPMkhVZftSXjJPsDh87z2WsNE1Fb3d3z+POVVQIdQ5ShJhqywdEgEgQQ1qwutsbFT4QM4DXFcALwi3YJqDD2bPx4/PGCg/OSw46NwAFA0nU7d7ObUYAHxF+wYMDUU8jiz19aG9TihEbyuS3oSavNmoT5Sm1thA/CkCLsvJ0In5XdnsIKkv+gCaSGZQ8QF7+AXrST0peBH8Ar9+grKfuS1Mgd/wBjb/0lmChvmBr14GgMy5qoiA/N+zcPSNfPN2fCoVF86KlDQxqvc93tl8DaBxALcAi/qLqKuaWpalAffsOz8iB4ZRSzYIymNJLgAEAYsJkJOLW//gAAAAASUVORK5CYII="}]<br>}</pre>

## OpenAPI

````json POST /message/sendTransactional
{
  "openapi": "3.0.4",
  "info": {
    "title": "Engage public API",
    "version": "1"
  },
  "servers": [
    {
      "url": "https://your-engage-domain.com/api/rest"
    }
  ],
  "tags": [
    {
      "name": "Address Attributes"
    },
    {
      "name": "Async"
    },
    {
      "name": "Audit Log"
    },
    {
      "name": "Automation"
    },
    {
      "name": "Blacklist"
    },
    {
      "name": "CMS"
    },
    {
      "name": "Contact"
    },
    {
      "name": "Content"
    },
    {
      "name": "Coupon"
    },
    {
      "name": "Draft Message"
    },
    {
      "name": "Ecommerce"
    },
    {
      "name": "Group"
    },
    {
      "name": "Group Attributes"
    },
    {
      "name": "Landing Page"
    },
    {
      "name": "Member Attributes"
    },
    {
      "name": "Membership"
    },
    {
      "name": "Message"
    },
    {
      "name": "Meta"
    },
    {
      "name": "Mobile Push"
    },
    {
      "name": "Prepared Message"
    },
    {
      "name": "Process"
    },
    {
      "name": "Profile Attributes"
    },
    {
      "name": "Related Data"
    },
    {
      "name": "Segmentation"
    },
    {
      "name": "System"
    },
    {
      "name": "System User"
    },
    {
      "name": "Usage Statistics"
    },
    {
      "name": "User"
    },
    {
      "name": "Whiteboard"
    }
  ],
  "paths": {
    "/message/sendTransactional": {
      "post": {
        "tags": [
          "Message"
        ],
        "summary": "Send a transactional message",
        "description": "Sends a prepared message as a transactional message, and adds user as member to group the prepared message belong to. <br> Please be aware this may cause that user to be unexpectedly subscribed or re-subscribed to that group. <br>Attachments may be added as part of the JSON payload. If you wish to attach a file to the message, the data must be Base64 encoded <br>and added as the value of the attachment’s content string, as demonstrated below. Request body example with attachment: <br><br><pre>{<br>\"parameters\":<br>  [{\"name\" : \"Parameter Name 1\",\"value\" : \"Parameter Value 1\"},<br>   {\"name\" : \"Parameter Name 2\",\"value\": \"Parameter Value 2\"}],<br>    \"attachments\":<br>    [{\"name\" : \"twitter_logo.png\",<br>      \"contentType\" : \"image/png\",<br>      \"content\": \"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\"}]<br>}</pre>",
        "operationId": "sendTransactional",
        "parameters": [
          {
            "name": "messageId",
            "in": "query",
            "description": "ID of the message or prepared message",
            "schema": {
              "type": "integer",
              "format": "int64"
            }
          },
          {
            "name": "externalTransactionFormula",
            "in": "query",
            "description": "External transactional identifier. If not available, \"null\" can be used.",
            "schema": {
              "type": "string"
            }
          },
          {
            "name": "recipientId",
            "in": "query",
            "description": "ID of the user",
            "schema": {
              "type": "integer",
              "format": "int64"
            }
          },
          {
            "name": "senderProfileName",
            "in": "query",
            "description": "TLS sender profile. Requires a Feature Switch and setting up a profile name in Mapp Engage. (optional)",
            "schema": {
              "type": "string"
            }
          }
        ],
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/MessageContent"
              }
            }
          },
          "x-bodyName": "body"
        },
        "responses": {
          "204": {
            "description": "",
            "content": {
              "application/octet-stream": {}
            }
          },
          "400": {
            "description": "Missing parameter (messageId/recipientId) or parameter value, for example:<br><br><pre>{<br>  \"errorActor\": \"CLIENT\",<br>  \"errorCode\": \"MISSING_PARAMETER\",<br>  \"message\": \"Parameter 'messageId' is mandatory but no value was specified.\",<br>  \"parameterName\": \"messageId\",<br>  \"propertyName\": null,<br>  \"value\": \"null\"<br>}</pre><br><br>Message ID or recipient does not exist, for example:<br><br><pre>{<br>  \"errorActor\": \"CLIENT\",<br>  \"errorCode\": \"NO_SUCH_OBJECT\",<br>  \"message\": \"Message with id=24011454555 does not exist.\",<br>  \"objectType\": \"Message\",<br>  \"propertyName\": \"id\",<br>  \"propertyValue\": \"24011454555\"<br>}</pre>",
            "content": {
              "application/octet-stream": {}
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "MessageContent": {
        "type": "object",
        "properties": {
          "parameters": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/Attribute"
            }
          },
          "attachments": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/Attachment"
            }
          }
        }
      },
      "Attribute": {
        "type": "object",
        "properties": {
          "name": {
            "type": "string"
          },
          "value": {
            "type": "string"
          }
        }
      },
      "Attachment": {
        "type": "object",
        "properties": {
          "name": {
            "type": "string"
          },
          "contentType": {
            "type": "string"
          },
          "content": {
            "type": "string"
          }
        }
      }
    }
  }
}
````