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Overview

The message endpoints in this section allow you to send messages only when the WhatsApp conversation window is open (within the 24-hour period). This is a rule from the official WhatsApp Business API.
The 24-hour conversation window opens when the customer sends a message to you. Outside this window, you can only send messages using Meta-approved templates. The messages in this section do not work outside the conversation window.

Inside the window (24h)

Did the customer send you a message? Great, the window is open. You can use any endpoint in this section to reply with text, image, audio, video, document, etc.

Outside the window (after 24h)

If the customer has not sent a message in the last 24 hours, the only way to start a conversation is by sending a message template previously approved by Meta. Templates are pre-defined messages that you create and submit for approval in the Meta dashboard.
In Z-API (unofficial connection) this limitation didn’t exist — you could send messages at any time. In the official API, this rule is mandatory and cannot be bypassed.

To send a message, you need the recipient’s phone number, including the country code.
FormatExample
Country code + area code + number5511999999999

API Response

When you send a message, the API returns the same response structure you already know from Z-API. This means no changes are needed in your code that processes the returns — the fields, types, and formats are identical. Example response when sending a message:
{
  "zaapId": "3999984263738042930CD6ECDE9VDWSA",
  "messageId": "D241XXXX732339502B68"
}
We maintain full compatibility with the Z-API response structure. If your application already handles these fields, it will continue working without changes.

Store the messageId

It’s very important that you store the messageId returned, as it’s needed for future operations like replying, marking as read, or deleting messages.
Without the messageId, you won’t be able to reference the message later to reply, react, or delete.

Text formatting

You can format message text using WhatsApp special characters:
FormattingSyntaxResult
Bold*text*text
Italic_text_text
Strikethrough~text~text
Monospace```text```text