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POST
/
campaigns
/
{campaignId}
/
schedule
Schedule a campaign
curl --request POST \
  --url https://app.lettr.com/api/campaigns/{campaignId}/schedule \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "scheduled_at": "2026-06-01T09:00:00+00:00"
}
'
{
  "message": "Campaign scheduled for delivery.",
  "data": {
    "id": "0193e6a8-1f3a-7c2a-b9e2-1aa1d2e5d3f0",
    "name": "Spring Sale",
    "status": "sent",
    "sent_count": 124,
    "created_at": "2026-05-01T09:00:00+00:00",
    "stats": {
      "injections": 0,
      "deliveries": 0,
      "bounces": 0,
      "spam_complaints": 0,
      "opens": 0,
      "unique_opens": 0,
      "clicks": 0,
      "unique_clicks": 0,
      "unsubscribes": 0
    },
    "subject": "<string>",
    "from_email": "jsmith@example.com",
    "from_name": "<string>",
    "reply_to": "jsmith@example.com",
    "scheduled_at": "2023-11-07T05:31:56Z",
    "total_recipients": 123,
    "sent_at": "2023-11-07T05:31:56Z"
  }
}

Documentation Index

Fetch the complete documentation index at: https://docs.lettr.com/llms.txt

Use this file to discover all available pages before exploring further.

Schedules a campaign for future delivery, or reschedules an already-scheduled campaign to a new time. The campaign transitions to (or stays) scheduled and is dispatched automatically at the given time. Requires the campaigns:write scope. Not available to sandbox keys.

Authorizations

​
Authorization
string
header
required

API key for authentication

Path Parameters

​
campaignId
string<uuid>
required

Campaign ID

Body

application/json
​
scheduled_at
string<date-time>
required

Future delivery time (ISO 8601). Include a timezone offset (e.g. +02:00 or Z); a value without an offset is interpreted as UTC. Must be in the future.

Example:

"2026-06-01T09:00:00+00:00"

Response

Campaign scheduled for delivery.

​
message
string
required
Example:

"Campaign scheduled for delivery."

​
data
object

The updated campaign. Present on success; omitted in the rare case the campaign cannot be re-read immediately after the action (e.g. it was concurrently deleted).