Documentation
Send messages
Sending is a single authenticated POST. The message goes out from the connected business number you name, so the customer sees the number they already recognise.
Send a text message
POST /messages
201 Created
Send a document
POST /messages
201 Created
Avoiding duplicate sends
Include an idempotency key with the request when a retry is possible — for example when the send is triggered by a queue consumer that may re-run. A repeated request with the same key returns the original result instead of sending a second message.
Sending responsibly
What you send, to whom, and how often is your decision and your responsibility, including consent and any messaging rules that apply in your market. WhatSyncs provides the transport, not the legal basis.
Everything on this page works on the Free plan, including webhooks and full API access.
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