The WhatsApp API returns a keys value for each message it accepts. A key confirms acceptance, not delivery. Delivery status arrives through your webhook.
Send your first test to a phone number you own that has opted in to WhatsApp messages.
Check the result in the InOne panel
Save each key from the response.
For template messages, open the WhatsApp templates page in the InOne panel and check that the template is approved.
Open the WhatsApp Transactional Analytics page in the InOne panel and check that the Sent, Delivered, and Opens totals increase. The panel shows totals only; the delivery status of an individual message is reported through your webhook. Match each webhook event to your request by its key.
Check your webhook log for the delivery status of each key.
Confirm that the message arrives in WhatsApp.
Interpret the response
The send endpoint accepts or rejects the whole request.
200 OK: The request was accepted. The response contains one key per message, in the same order as your messages array. Save every key; it is attached to every webhook event for that message.
400 Bad Request: The request was rejected, and no message was queued. No keys are returned. Read the errorCode in the body:
2001: The body could not be parsed. Check the JSON structure.
2002: A field failed validation. The error message names the field, for example, a missing phoneNumber or an invalid coupon_code.
2003: The request is valid, but Insider One cannot send it, for example, when WhatsApp or the transactional feature is not active for the account.
A key confirms acceptance, not delivery. For authentication and rate limit errors, see API Status and Error Codes.
The whatsapp- key in the response identifies your request. Meta's own message ID appears later in webhook events. Template errors are not reported in the send response. Insider One does not check the template name, approval status, or parameter count when it accepts the request. Meta checks them when the message is sent, so an unapproved template (error 132001) or a parameter count mismatch (error 132000) returns 200 OK with a key, and the error arrives later as a failed event on your webhook. These messages also appear under Unsuccessful Messages in WhatsApp Transactional Analytics.
Reproduce a failure in Postman
Open the endpoint page and select Run in Postman. The Insider One Postman documentation opens at that endpoint.
In the top right corner of the Postman documentation, select Run in Postman.
In the Fork collection into your workspace window, select Fork Collection. Postman opens the collection in the Postman app or in your browser.
Select the environment that holds your API key.
In the Body tab, select raw and paste the payload from your integration.
Select Send and compare the response with your integration log.
Send one message at a time to find the one that fails.
Remove the API key and phone numbers before you share the request or response.
To see a failed event on your webhook, send a template message with one variable missing. The send response returns 200 OK with a key; the error 132000 arrives on your webhook for that key.
For more information, see Insider One APIs in Postman and API Status and Error Codes.