LineDevelopers

Preview encoding, segments, cost, and policy

POST/api/v1/messages/preview
Bearer key, test or live

Request body

fromstringrequired

An approved number in E.164 format, or an approved sender name such as ACMEDENTAL. A sender name is one-way and sends only to UK and Irish numbers.

tostringrequired

One recipient in E.164 format.

bodystring

The text. Send either body or template_id.

template_idstring · uuid

An active template. Line renders it with variables before it counts segments.

variablesobject

A value for every {{variable}} in the template.

send_atstring · date-time

Schedule the send, up to 35 days ahead. Include an offset, such as Z or +01:00. Credits are reserved at acceptance and released if the send is canceled.

expires_atstring · date-time

Do not send after this time. A message still waiting then ends as expired and its credits are released.

client_referencestring
metadataobject
max_segmentsinteger

Reject the send when the encoded body exceeds this limit. The service maximum is 10.

max_creditsnumber

Reject the send when the estimate exceeds this decimal credit ceiling.

Responses

200A non-sending preview with the rendered body and a policy result.
Plus 400, 401, 403, 429, 503. See Errors.
PreviousSend or schedule one SMSNextSend up to 500 messages in one request
curl -X POST 'https://staging.useline.io/api/v1/messages/preview' \
  -H "Authorization: Bearer $LINE_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
    "from": "+447700900123",
    "to": "+447700900456",
    "body": "Hi Sam, your engineer arrives between 10 and 12 tomorrow."
  }'