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

# Sending messages

> Use the Tatango Transactional Message activity in a Journey Builder journey

## Build the journey

Create a journey whose entry source is backed by a data extension; a **Data Extension** entry source and an **API Event** both work. The entry data extension must contain a phone number column and a subscriber key column; beyond that, its shape is up to you: the activity reads whichever columns you select, and every column is available as a merge tag.

Drag the **Tatango Transactional Message** activity from the Messages section of the palette onto the canvas, then open it to configure.

<Frame>
  <img src="https://mintcdn.com/momogood/Dro8ZZqtqv-L8tBN/images/sfmc/activity-on-canvas.png?fit=max&auto=format&n=Dro8ZZqtqv-L8tBN&q=85&s=4da5b53baa1cd17aa5325a35ce457521" alt="A journey canvas with an entry event and the Tatango Transactional Message activity placed after it" width="845" height="552" data-path="images/sfmc/activity-on-canvas.png" />
</Frame>

## Configure the activity

<Frame caption="The activity configured for an SMS send">
  <img src="https://mintcdn.com/momogood/Dro8ZZqtqv-L8tBN/images/sfmc/activity-config.png?fit=max&auto=format&n=Dro8ZZqtqv-L8tBN&q=85&s=fbd60691a5f657b1ba819cef00ed9f1d" alt="The Transactional Message Activity modal configured for an SMS send" width="651" height="832" data-path="images/sfmc/activity-config.png" />
</Frame>

| Field                      | Description                                                                                     |
| -------------------------- | ----------------------------------------------------------------------------------------------- |
| Entry Event Data Extension | Auto-populated from the journey's entry event; read-only.                                       |
| Phone Number Column        | The entry data extension column holding the recipient's phone number.                           |
| Subscriber Key Column      | The entry data extension column holding the contact's subscriber key, recorded with every send. |
| Message Channel            | SMS or MMS. MMS allows multimedia content and longer messages.                                  |
| Message Content            | The message body: up to 160 characters for SMS or 3,500 for MMS.                                |

Selecting **MMS** adds three fields:

| Field          | Description                                                                                                              |
| -------------- | ------------------------------------------------------------------------------------------------------------------------ |
| Subject Line   | The MMS subject, up to 40 characters.                                                                                    |
| Attachment URL | A publicly accessible URL for the attachment: JPEG, PNG, or WebP images (1 MB), GIFs (0.6 MB), or MP4/MPEG video (2 MB). |
| SMS Fallback   | An SMS message, up to 160 characters, sent to recipients whose devices can't receive the MMS message.                    |

Each activity instance carries its own configuration, so a journey can contain several Tatango Transactional Message activities with different content, such as one message per path of a decision split or a follow-up later in the journey.

## Send a test message

Click **Send Test Message** in the activity to deliver the configured message to a phone number you enter, before the journey goes live.

<Frame>
  <img src="https://mintcdn.com/momogood/Dro8ZZqtqv-L8tBN/images/sfmc/test-message.png?fit=max&auto=format&n=Dro8ZZqtqv-L8tBN&q=85&s=c0053725acb25b60205375af0926f92d" alt="The Send Test Message dialog with a phone number entered" width="399" height="241" data-path="images/sfmc/test-message.png" />
</Frame>

Test sends are recorded in the `tatango_messages` data extension with `TEST MESSAGE` as their journey and activity IDs, so they are easy to exclude from reporting. The [example report query](/messaging/sfmc/reporting) shows you how to do that.

## Activate

Click **Done** to validate and save the activity configuration, then **Activate** the journey and follow the prompts. Once activation succeeds, contacts entering the journey receive messages.

<Note>
  Journey Builder's validation may show a "Missing Message Activity" recommendation because it doesn't recognize custom activities as messaging activities. It's safe to ignore and doesn't block activation.
</Note>

<Frame>
  <img src="https://mintcdn.com/momogood/Dro8ZZqtqv-L8tBN/images/sfmc/activate-journey.png?fit=max&auto=format&n=Dro8ZZqtqv-L8tBN&q=85&s=e9c5e6e7e9537e173722e8c712c64fec" alt="The Validation Results panel showing the Missing Message Activity recommendation and the Activate button" width="1044" height="969" data-path="images/sfmc/activate-journey.png" />
</Frame>

## Compliance is automatic

Before every send, the activity checks the contact against the `tatango_subscribers` data extension:

* Contacts who opted out (for example, by replying STOP to a previous message) are skipped.
* Contacts whose numbers were cleaned because they can't receive text messages are skipped.

Skipped sends are recorded in `tatango_messages` with a send status of `skipped` and a skip reason, so your reporting still sees the full picture. See the [data extensions](/messaging/sfmc/data-extensions) page for how opt-outs and cleans are captured.