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# SMS status callback

POST 

Payload sent by SignalWire to your SMS Status Callback URL when the status of an SMS/MMS message changes.

Configure this callback using the `StatusCallback` parameter when
[sending an outgoing message](/docs/compatibility-api/rest/messages/create-message).

There are 8 possible message statuses:

| Status        | Description                                                                              |
| ------------- | ---------------------------------------------------------------------------------------- |
| `queued`      | The API request was processed and the message is waiting to be sent.                     |
| `sending`     | The message is being transmitted to the nearest upstream carrier.                        |
| `sent`        | The nearest upstream carrier has accepted the message.                                   |
| `delivered`   | The nearest upstream carrier confirmed receipt of the message.                           |
| `undelivered` | SignalWire received notice from the upstream carrier that the message was not delivered. |
| `failed`      | SignalWire could not send the message. There is no charge for failed messages.           |
| `receiving`   | SignalWire has received and is currently processing an inbound message.                  |
| `received`    | The inbound message has been received by a number in your account.                       |

SignalWire only marks a message as `delivered` when it receives a Delivery Receipt (DLR)
from the receiving carrier confirming entry into the end carrier's network. `sent` means the message
left SignalWire and reached the downstream peer. Some carriers send delayed DLRs; others send none
at all. MMS messages never receive DLRs, so they will only ever reach `sent` status.

Status callbacks are advisory, best-effort notifications — delivery can be delayed or fail silently, so don't gate time-critical actions on receiving one. See [Status callback reliability](/docs/platform/webhooks#status-callback-reliability).

Reference: https://signalwire.com/docs/compatibility-api/rest/messages/webhooks/sms-status-callback

## Request

### Payload

- `MessageStatus` (enum, required) — The current status of the message at the time of the callback. One of: `queued`, `sending`, `sent`, `delivered`, `undelivered`, `failed`, `receiving`, `received`.
  - Allowed values: `queued`, `sending`, `sent`, `delivered`, `undelivered`, `failed`, `receiving`, `received`
- `MessageSid` (string, required) — The unique ID of this message.
- `AccountSid` (string, required) — The unique ID of the project this message is associated with.
- `From` (string, required) — The From number of the message.
- `To` (string, required) — The To number of the message.
- `Body` (string, required) — The body of the message.
- `NumMedia` (integer, required) — The number of media files that were included with the message.
- `NumSegments` (integer, required) — The number of segments that make up the entire message. If the body exceeds 160 GSM-7 characters or 70 UCS-2 characters, it is automatically split into smaller segments that are annotated for reconstruction on the recipient handset.
- `ErrorCode` (string, optional) — If the message has failed or is undelivered, the error code may provide more information about what went wrong.