To connect your Custom App with SyncMate, you need to follow the easy steps below:
Step 1
First of all, you will need to connect your WhatsApp with SyncMate, If you haven’t done this yet, please follow our Configuration guide.
Step 2
Copy the API key of the custom app.

TL;DR: Need more examples? Checkout our Postman Collection to test these endpoints directly in your environment. #
Step 3: Making API Requests
You can send messages using either our Single Messaging or Bulk Messaging endpoints. All API requests require your API Key to be passed as a Bearer token in the authorization header.
Required Headers:
The parameters that are required to make a post request on the above URL:
headers = {
"Authorization": "Bearer {bearer_token}",
"Content-Type": "application/json"
}
1. Single Messaging Endpoint #
POST https://app.assistro.co/api/v1/wapushplus/single/message
Use this endpoint to send a message to a single contact.
Request Body:
Request body = {
"msgs": [
{
"number": 911234567890, //Whatsapp number with country code
"message": "Hi! How are you?",
"media": [
{
"media_base64": "BASE64_STRING (without mime_type in the beginning)",
"file_name": "YOUR_FILENAME"
}
]
}
]
}
Notes: * "number": Must be a string containing the WhatsApp number with the country code (no + sign).
-
"type": Use1for direct messages,2for groups, or3for newsletters/channels. -
"media_base64": (Optional) Provide the raw base64 string without the MIME type prefix (e.g., do not includedata:image/png;base64,).
2. Bulk Messaging Endpoint #
POST https://app.assistro.co/api/v1/wapushplus/bulk/message
Use this endpoint to send multiple messages in a single API call.
Request Body:
Request body = {
"msgs": [
{
"number": 911234567890, //Whatsapp number with country code
"message": "Hi! How are you?",
"media": [
{
"media_base64": "BASE64_STRING (without mime_type in the beginning)",
"file_name": "YOUR_FILENAME"
}
]
},
{
"number": 911234567890, //Whatsapp number with country code
"message": "Hey there!"
},
{
"number": 911234567890, //Whatsapp number with country code
"message": "Good Morning!"
}
]
}
Common Status Codes:
-
200 OK: Your request was successful and messages are queued for delivery.
-
400 Bad Request: There is a formatting error in your request body (e.g., missing a required field like
"number"or"type"). -
401 Unauthorized: Your API key is missing or invalid. Check your Bearer token.
-
500 Internal Server Error: An unexpected error occurred on our end.
