Create opt-in confirmations

Sends the opt-in confirmation message by WhatsApp to chosen contacts who have not confirmed yet. Call without plan_id for a preview, then again with the plan_id and a new Idempotency-Key. Returns the preview or the queued count.

POST /v1/optin-confirmations

Permission	`sends:create` and `newsletters:send` (all permissions)
Risk	Send (reaches other people)
Idempotency-Key	Required (how it works)
Safe to repeat	Safe to repeat with the same Idempotency-Key: the first answer comes back and nothing is done twice.
Rate limit class	`send` (120 requests per minute per key)
Confirmation	Preview first, then the call with the plan ID
MCP tool	`send_optin_confirmations`
Since version	2026-10-25

#What it does

Sends WhatsApp messages to contacts.
Needs a confirmation step (a preview first).
Safe to repeat with the same Idempotency-Key.

#Request

Header

Name	Required	Description
`Authorization`	yes	`Bearer <key>`
`Idempotency-Key`	yes	A unique value for this operation, for example a UUID (1 to 255 visible ASCII characters).

Body (JSON)

Name	Type	Required	Description
`contact_ids`	array of string	yes	The contacts that should get the confirmation message (1 to 500). Only contacts with opt-in status none qualify. up to 500 items
`plan_id`	string	no	Plan ID from the preview call. Leave out to get a preview.

#Examples

curlPythonTypeScript

curl -X POST "https://api.smartchat.marketing/v1/optin-confirmations" \
  -H "Authorization: Bearer $SMARTCHAT_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
  "contact_ids": [
    "con_0f8c1a2e4b7d4c3e9a5b6d7e8f901234"
  ]
}'

import os
import uuid
import requests

response = requests.post(
    "https://api.smartchat.marketing/v1/optin-confirmations",
    headers={
        "Authorization": "Bearer " + os.environ["SMARTCHAT_API_KEY"],
        "Idempotency-Key": str(uuid.uuid4()),
    },
    json={
        "contact_ids": [
            "con_0f8c1a2e4b7d4c3e9a5b6d7e8f901234",
        ],
    },
)
response.raise_for_status()
print(response.json())

const response = await fetch("https://api.smartchat.marketing/v1/optin-confirmations", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.SMARTCHAT_API_KEY}`,
    "Idempotency-Key": crypto.randomUUID(),
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "contact_ids": [
      "con_0f8c1a2e4b7d4c3e9a5b6d7e8f901234"
    ]
  }),
});
if (!response.ok) throw new Error(await response.text());
console.log(await response.json());

Response (202):

{
  "object": "optin_confirmation_plan",
  "plan_id": "pln_5e6f7a8b9c0d41e2f3a4b5c6d7e8f901",
  "expires_at": "2026-10-25T09:51:07Z",
  "recipients": 1,
  "days": 1,
  "daily_limit": 250,
  "can_start": true,
  "template_state": "sendable",
  "truncated": false
}

#Response

Status 202. Every response has the headers Request-Id, SmartChat-Version and X-RateLimit-*.

#Errors

Code	Status	When
`bad_request`	400	The request could not be read.
`idempotency_key_invalid`	400	The 'Idempotency-Key' header must be 1 to 255 visible ASCII characters.
`idempotency_key_required`	400	This call needs an 'Idempotency-Key' header.
`missing_parameter`	400	A required field is missing.
`unknown_parameter`	400	A field is not known.
`api_key_expired`	401	This API key has expired.
`api_key_invalid`	401	This API key is not valid.
`api_key_revoked`	401	This API key was revoked.
`authentication_required`	401	No API key was sent. Send 'Authorization: Bearer <key>'.
`account_blocked`	403	This account is blocked.
`insufficient_scope`	403	This key lacks a required permission.
`ip_not_allowed`	403	This IP address is not allowed for this key.
`subscription_locked`	403	The subscription or payment state blocks this function.
`plan_not_found`	404	No plan with this ID exists.
`conflict`	409	The state of the object does not allow this.
`idempotency_in_progress`	409	A request with this idempotency key is still running.
`plan_already_used`	409	The plan was already used.
`plan_changed`	409	The content or audience changed after the preview.
`plan_mismatch`	409	The plan belongs to another account, key, action or request.
`plan_expired`	410	The plan is older than 10 minutes.
`audience_empty`	422	The audience has no reachable contacts.
`idempotency_key_reused`	422	This idempotency key was already used with a different request.
`template_not_approved`	422	The template is not approved.
`validation_failed`	422	A field is not valid.
`rate_limited`	429	Too many requests. Wait and try again.
`internal_error`	500	Something went wrong on our side.
`service_unavailable`	503	The service is temporarily unavailable.

All errors use one format.