Returns a single SMS message: its current delivery status, segment breakdown, cost, and failure detail when it failed. The `status` advances asynchronously as delivery progresses, and `cost` is null until the message has been priced, so poll this endpoint (or subscribe to `sms.*` webhook events) after a send to confirm delivery. To scan messages in bulk, use [List SMS messages](/docs/api/reference/list-sms-messages) instead. ID of the message (`sms_`-prefixed), as returned in the send response's `id` field. ID of the message (`sms_`-prefixed), assigned when the send is accepted. Pass it as `message_id` to the get-message endpoint. Whether the message was sent from a Bird sender (`outbound`) or received from a subscriber (`inbound`). Possible values: `outbound`, `inbound` Recipient phone number in E.164 format. Sender the message was sent from: an E.164 number, an alphanumeric sender ID, or a short code. The message body as sent. For a template send, this is the rendered text after parameter substitution. Content classification supplied on the send. Null for inbound messages. Segment breakdown for the body. Number of segments the body is split into. Each segment is a billable unit. Encoding used for the body. `GSM_7BIT` fits 160 characters in a single segment (153 per part when multi-segment); `UCS2` is used when the body contains any character outside the GSM 03.38 alphabet (emoji, CJK, some accented characters) and fits 70 characters in a single segment (67 per part when multi-segment). Possible values: `GSM_7BIT`, `UCS2` Character count of the body under the selected encoding. Cost of the message. Null until the message has been priced. ISO 4217 currency code for the cost amount. Omitted when the cost is not denominated in a currency (for example a zero-priced internal send). Total cost as a decimal string: the per-segment rate multiplied by the segment count, plus any surcharges. Per-component cost breakdown. Returned on single-message reads; omitted from list rows. Per-segment price as a decimal string. Number of billable segments. ISO 3166-1 alpha-2 destination country the price was resolved for. Carrier surcharge component as a decimal string (for example US 10DLC fees). `0.0000` when none applies. Structured `{name, value}` filter labels applied to this message. Tag name. ASCII letters, digits, underscore, and hyphen only. Case-sensitive. Maximum 32 characters. Tag value. ASCII letters, digits, underscore, and hyphen only. Case-sensitive. Maximum 64 characters. Arbitrary JSON metadata stored on the message and echoed in webhook payloads. How long, in seconds, Bird keeps trying to deliver before the message transitions to `expired`. Carrier that handled the message, when known. Populated once a delivery receipt identifies it. Mobile country code and mobile network code of the carrier, when known. Failure detail on a terminally failed or rejected message. Present only when the message failed. Bird-stable failure reason. `invalid_destination`: the number is not assigned, ported out, or malformed. `unreachable`: handset off or out of coverage. `blocked_by_carrier`: the carrier filtered the message. `blocked_by_recipient`: the recipient device blocked the sender. `landline_unreachable`: the destination is a landline that does not accept SMS. `content_rejected`: the carrier rejected the content. `sender_unregistered`: the sender is not registered for the destination. `recipient_opted_out`: the recipient is on a suppression list. `provider_unavailable`: an upstream failure after retries. `insufficient_balance`: the workspace wallet had insufficient balance to send the message. `unknown`: an unmapped failure. Possible values: `invalid_destination`, `unreachable`, `blocked_by_carrier`, `blocked_by_recipient`, `landline_unreachable`, `content_rejected`, `sender_unregistered`, `recipient_opted_out`, `provider_unavailable`, `insufficient_balance`, `unknown` Human-readable explanation of the failure. Raw carrier-supplied error code, when available, for low-level debugging. When the failure occurred. When the message was accepted (outbound) or received (inbound). When the message was handed to the carrier. Null until then. When delivery was confirmed. Null until then.