***

id: d93805fe-328c-4957-b304-cafc0b3082c5
title: SignalWire.Relay.MessagingAPI
slug: /dotnet/reference/messaging
max-toc-depth: 3
----------------

[sendresult]: /docs/server-sdk/v2/dotnet/reference/messaging/send-result

[sendsource]: /docs/server-sdk/v2/dotnet/reference/messaging/send-source

This represents the API interface for the Messaging Relay Service. This object is used to make requests related to managing SMS and MMS messages.

## Methods

### Send

Send an outbound SMS or MMS message.

**Parameters**

| Parameter | Type                                                  | Required                                   | Description                                                                                                 |
| --------- | ----------------------------------------------------- | ------------------------------------------ | ----------------------------------------------------------------------------------------------------------- |
| `context` | string                                                | <span class="required-arg">required</span> | The context to receive inbound events.                                                                      |
| `to`      | string                                                | <span class="required-arg">required</span> | The phone number to send to.                                                                                |
| `from`    | string                                                | <span class="required-arg">required</span> | The phone number to place the message from. *Must be a SignalWire phone number or short code that you own.* |
| `source`  | [`SignalWire.Relay.Messaging.SendSource`][sendsource] | <span class="required-arg">required</span> | The message. May be populated by a body string or a list of media URLs.                                     |
| `tags`    | List\<string>                                         | <span class="optional-arg">optional</span> | Tags to tag the message with for searching in the UI. <br />*Default: Empty*                                |

**Returns**

[`SignalWire.Relay.Messaging.SendResult`][sendresult] - The result object to interact with.

**Examples**

> Send a message.

```csharp
SendResult resultSend = client.Messaging.Send(validContext, "+1XXXXXXXXXX", "+1YYYYYYYYYY");

if (resultSend.Successful)
{
    // Message has been queued, you can subscribe to MessagingAPI.OnMessageStateChange to receive further updates
}
```

## Events

All these events can be used to track the message lifecycle and instruct SignalWire on what to do for each different state.

## State Events

To track the state of a sent message.

| Property               | Description                                                                                                                                                          |
| :--------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `OnMessageStateChange` | The message is changing state, generalized event for the following events.                                                                                           |
| `OnMessageDelivered`   | The message has been delivered. Due to the nature of SMS and MMS, receiving a `delivered` event is not guaranteed, even if the message is delivered successfully.    |
| `OnMessageFailed`      | The message delivery failed.                                                                                                                                         |
| `OnMessageInitiated`   | The message delivery has been started.                                                                                                                               |
| `OnMessageQueued`      | The message has been put into the queue for delivery.                                                                                                                |
| `OnMessageSent`        | The message has been sent for delivery.                                                                                                                              |
| `OnMessageUndelivered` | The message has not been delivered. Due to the nature of SMS and MMS, receiving an `undelivered` event is not guaranteed, even if the message fails to be delivered. |

## Receive Events

| Property            | Description                  |
| :------------------ | :--------------------------- |
| `OnMessageReceived` | A message has been received. |