Schedule SMS Campaign

Schedule a configured SMS campaign for immediate processing or a future time.

Scheduling requires an SMS sender ID in the workspace, sufficient prepaid SMS balance, and successful automated campaign review. The campaign must have a name, message, and audience.

---

Endpoint

POST https://api.campaignlark.com/v1/sms-campaigns/:id/schedule

---

Path Parameters

Parameter	Type	Required	Description
id	string	required	Campaign ID as a MongoDB ObjectID hex string.

---

Request Body

Field	Type	Required	Description
schedule_type	string	required	NOW or LATER.
scheduled_at	string	required for LATER	Future RFC3339 timestamp.

---

Sample Request

POST https://api.campaignlark.com/v1/sms-campaigns/64f1a2b3c4d5e6f7a8b9c0d1/schedule
Content-Type: application/json

{
  "schedule_type": "LATER",
  "scheduled_at": "2025-07-01T09:00:00Z"
}

---

Response

Success — 200 OK

{
  "error": null,
  "data": {
    "id": "64f1a2b3c4d5e6f7a8b9c0d1",
    "status": "QUEUED",
    "scheduled_at": "2025-07-01T09:00:00Z"
  }
}

For NOW, scheduled_at is omitted from the response.

---

Errors

Status	Message	Cause
400	Invalid request body.	The request body could not be parsed.
400	Please provide a campaign ID.	id is missing.
400	We could not find the campaign you are looking for.	The ID is malformed or the campaign does not exist in the workspace.
400	Invalid schedule type. Must be 'NOW' or 'LATER'.	schedule_type is not supported.
400	Scheduled date and time is required when schedule type is 'LATER'.	scheduled_at was omitted for LATER.
400	Invalid scheduled date format. Please provide a valid ISO 8601 UTC timestamp.	scheduled_at is not a valid RFC3339 timestamp.
400	Scheduled date must be in the future.	The requested time is not in the future.
400	Please enter a valid date and time.	The scheduled date could not be parsed while creating the processing job.
400	Only draft campaigns can be scheduled.	The campaign is not in DRAFT status.
400	Please provide a name for this campaign before scheduling.	The campaign has no name.
400	Please provide a message for this campaign before scheduling.	The campaign has no message.
400	Please configure an audience for this campaign before scheduling.	The campaign has no audience.
400	Please add an SMS sender ID under SMS Marketing before scheduling this campaign.	The workspace has no SMS sender ID.
400	We could not check your SMS balance. Please try again later.	The balance could not be checked.
400	Your available SMS balance is $<available>, but at least $<minimum> is required to start a campaign. Please visit Billing to top up your SMS balance.	The prepaid SMS balance is below the scheduling minimum.
400	We couldn't complete the automated review of this campaign. Please try again in a few minutes.	Automated review could not complete.
400	This campaign was flagged by automated review. Please contact support if you believe this is a mistake.	Automated review classified the campaign as spam.
400	Failed to queue SMS campaign for processing.	The campaign processing job could not be queued.