Preview an SMS
const url = 'https://api.connect.ms/v2/sms/preview';const options = { method: 'POST', headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'}, body: '{"content":"example","recipient":"example"}'};
try { const response = await fetch(url, options); const data = await response.json(); console.log(data);} catch (error) { console.error(error);}curl --request POST \ --url https://api.connect.ms/v2/sms/preview \ --header 'Authorization: Bearer <token>' \ --header 'Content-Type: application/json' \ --data '{ "content": "example", "recipient": "example" }'Works out how many parts a message would use, which encoding, and (when a recipient is given) the estimated cost. Nothing is sent.
Authorizations
Section titled “Authorizations”Parameters
Section titled “Parameters”Header Parameters
Section titled “Header Parameters”The API version to use, for example 2026-10-01. Defaults to the version set on your API key.
A unique value of up to 255 characters, so a retried request is not acted on twice. Required for keys in Strict API Mode.
Request Bodyrequired
Section titled “Request Bodyrequired”The message to preview.
The message to preview.
object
The message text to measure, up to 5,000 characters.
Recipient Number (E.164 format). When given, the cost for that destination is included.
Example generated
{ "content": "example", "recipient": "example"}Responses
Section titled “Responses”The parts, encoding and estimated cost.
How a message would be sent, without sending it.
object
The number of SMS parts the content would be split into.
How the content is encoded on the network: gsm7 (the standard alphabet, 160 characters in a single-part message) or ucs2 (70 characters in a single-part message, used when the content has characters outside the GSM alphabet).
An amount in each currency it can be priced in, as decimal strings with four decimal places. A currency with no price is null.
object
The amount in pounds sterling, e.g. “0.0350”.
The amount in euros, e.g. “0.0410”.
Example
{ "encoding": "gsm7"}The request is not valid. The detail field says why, and errors lists any problems by field name.
Why a request failed, in the RFC 9457 problem details format.
object
A URI identifying the kind of problem, ending in a code such as validation_failed, not_found, sending_blocked or rate_limited.
A short, fixed summary of the kind of problem.
The HTTP status code of the response.
What went wrong with this particular request, when there is more to say than the title.
For validation failures, the problems found, keyed by field name (nested fields as template.name, list items as messages[3]).
object
The id recorded for this error, matching the Request-Id header when one is sent. Quote it when contacting support.
Example generated
{ "type": "example", "title": "example", "status": 1, "detail": "example", "errors": { "additionalProperty": [ "example" ] }, "requestId": "example"}The API key or bearer token is missing or not valid, or the request signature could not be verified.
Why a request failed, in the RFC 9457 problem details format.
object
A URI identifying the kind of problem, ending in a code such as validation_failed, not_found, sending_blocked or rate_limited.
A short, fixed summary of the kind of problem.
The HTTP status code of the response.
What went wrong with this particular request, when there is more to say than the title.
For validation failures, the problems found, keyed by field name (nested fields as template.name, list items as messages[3]).
object
The id recorded for this error, matching the Request-Id header when one is sent. Quote it when contacting support.
Example generated
{ "type": "example", "title": "example", "status": 1, "detail": "example", "errors": { "additionalProperty": [ "example" ] }, "requestId": "example"}The caller is not allowed to do this.
Why a request failed, in the RFC 9457 problem details format.
object
A URI identifying the kind of problem, ending in a code such as validation_failed, not_found, sending_blocked or rate_limited.
A short, fixed summary of the kind of problem.
The HTTP status code of the response.
What went wrong with this particular request, when there is more to say than the title.
For validation failures, the problems found, keyed by field name (nested fields as template.name, list items as messages[3]).
object
The id recorded for this error, matching the Request-Id header when one is sent. Quote it when contacting support.
Example generated
{ "type": "example", "title": "example", "status": 1, "detail": "example", "errors": { "additionalProperty": [ "example" ] }, "requestId": "example"}A request with this Idempotency-Key is still being processed. Retry after the Retry-After header.
Why a request failed, in the RFC 9457 problem details format.
object
A URI identifying the kind of problem, ending in a code such as validation_failed, not_found, sending_blocked or rate_limited.
A short, fixed summary of the kind of problem.
The HTTP status code of the response.
What went wrong with this particular request, when there is more to say than the title.
For validation failures, the problems found, keyed by field name (nested fields as template.name, list items as messages[3]).
object
The id recorded for this error, matching the Request-Id header when one is sent. Quote it when contacting support.
Example generated
{ "type": "example", "title": "example", "status": 1, "detail": "example", "errors": { "additionalProperty": [ "example" ] }, "requestId": "example"}This Idempotency-Key was already used for a different request. Use a new key.
Why a request failed, in the RFC 9457 problem details format.
object
A URI identifying the kind of problem, ending in a code such as validation_failed, not_found, sending_blocked or rate_limited.
A short, fixed summary of the kind of problem.
The HTTP status code of the response.
What went wrong with this particular request, when there is more to say than the title.
For validation failures, the problems found, keyed by field name (nested fields as template.name, list items as messages[3]).
object
The id recorded for this error, matching the Request-Id header when one is sent. Quote it when contacting support.
Example generated
{ "type": "example", "title": "example", "status": 1, "detail": "example", "errors": { "additionalProperty": [ "example" ] }, "requestId": "example"}This API key requires an Idempotency-Key header on every POST and PATCH.
Why a request failed, in the RFC 9457 problem details format.
object
A URI identifying the kind of problem, ending in a code such as validation_failed, not_found, sending_blocked or rate_limited.
A short, fixed summary of the kind of problem.
The HTTP status code of the response.
What went wrong with this particular request, when there is more to say than the title.
For validation failures, the problems found, keyed by field name (nested fields as template.name, list items as messages[3]).
object
The id recorded for this error, matching the Request-Id header when one is sent. Quote it when contacting support.
Example generated
{ "type": "example", "title": "example", "status": 1, "detail": "example", "errors": { "additionalProperty": [ "example" ] }, "requestId": "example"}The service is temporarily unavailable. Retry after the Retry-After header.
Why a request failed, in the RFC 9457 problem details format.
object
A URI identifying the kind of problem, ending in a code such as validation_failed, not_found, sending_blocked or rate_limited.
A short, fixed summary of the kind of problem.
The HTTP status code of the response.
What went wrong with this particular request, when there is more to say than the title.
For validation failures, the problems found, keyed by field name (nested fields as template.name, list items as messages[3]).
object
The id recorded for this error, matching the Request-Id header when one is sent. Quote it when contacting support.
Example generated
{ "type": "example", "title": "example", "status": 1, "detail": "example", "errors": { "additionalProperty": [ "example" ] }, "requestId": "example"}