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POST
This endpoint sends a freeform (free-text) WhatsApp message to a recipient. Unlike template messages, freeform messages can contain any text but require an active 24-hour messaging window — meaning the recipient must have sent a message to your WhatsApp sender within the last 24 hours.
Freeform messages can only be sent during an active 24-hour messaging window. If the session has expired, you must send a template message first to re-initiate the conversation. Use the Session Status endpoint to check if a session is active.
This endpoint is rate-limited to 5 requests per second per user.

Request Body

sender_id
integer
required
The ID of the WhatsApp sender to send from (obtained from the Get Senders endpoint)
recipient_phone
string
required
The recipient’s phone number in international format (e.g., +1234567890)
message
string
The message content to send (max 4096 characters). Optional when media_url is provided — in that case it is used as the media caption. Audio files are the exception: WhatsApp does not support captions on audio, so the text is ignored when media_url points to an audio file. Either message or media_url is required.
media_url
string
Optional public URL of a file to send — an image, audio file, video, or document. The file must be reachable at a public URL (WhatsApp fetches it at send time). When set, message is used as the caption for images, videos and documents. Audio files cannot carry a caption — if you send an audio file, any message text is ignored. Either message or media_url is required.
filename
string
Optional filename shown to the recipient, mainly useful for documents (e.g. invoice.pdf).

Response Fields

success
boolean
Whether the message was sent successfully
conversation_id
integer
The ID of the conversation associated with this message
message_id
integer
The ID of the conversation message record
whatsapp_message_id
integer
The ID of the WhatsApp message record
message_sid
string
The Twilio message SID for tracking delivery
session_status
object
Updated session status after sending the message

Error Responses

402 Insufficient Balance
403 Session Expired
404 Not Found
503 Sender Offline

24-Hour Messaging Window

WhatsApp enforces a 24-hour messaging window policy:
  1. When a customer sends a message to your WhatsApp Business number, a 24-hour window opens.
  2. During this window, you can send freeform messages without restrictions.
  3. After the window expires, you must use a template message to re-initiate the conversation.
  4. Each new customer message resets the 24-hour timer.
Use the Session Status endpoint to check whether a session is active before attempting to send a freeform message.

Notes

  • Maximum message length is 4,096 characters (WhatsApp limit).
  • A file (image, audio, video, or document) can be attached with media_url. It must be hosted at a publicly reachable URL — WhatsApp fetches it at send time. When sending media, message is optional and is used as the caption. Audio is the exception: WhatsApp does not support captions on audio files, so when media_url points to an audio file the message text is not sent.
  • The sender must be online. Offline senders return a 503 error.
  • Message costs are automatically deducted from your account balance.
  • Rate limit: 5 requests per second per user.