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POST
/
messages
/
group
/
{accountId}
/
send
Send Group Message
curl --request POST \
  --url https://api.a1base.com/v1/messages/group/{accountId}/send \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --header 'X-API-Secret: <api-key>' \
  --data '
{
  "content": "<string>",
  "from": "<string>",
  "thread_id": "<string>",
  "service": "whatsapp",
  "attachment_uri": "<string>"
}
'
{
  "chat_group_id": "<string>",
  "from": "<string>",
  "body": "<string>",
  "status": "queued",
  "date_created": "2023-11-07T05:31:56Z"
}

​
Sending Group Messages:

  • The agent’s phone number must first be added to the group chat before messages can be sent.
  • You’ll need the thread_id of the group chat to send messages. This is provided when you create a group or in webhook events.

​
Example Request

​
Text Message to Group

POST /group/{accountId}/send
Headers:
  x-api-key: your_api_key
  x-api-secret: your_api_secret
  Content-Type: application/json

Body:
{
  "from": "+14155552671",
  "thread_id": "group-thread-id-123",
  "service": "whatsapp",
  "message": "Hello everyone in the group!"
}

​
Media Message to Group

To send a document to a group: 
POST /group/{accountId}/send
Headers:
  x-api-key: your_api_key
  x-api-secret: your_api_secret
  Content-Type: application/json

Body:
{
  "from": "+14155552671",
  "thread_id": "group-thread-id-123",
  "service": "whatsapp",
  "message_type": "media",
  "media_url": "https://example.com/documents/report.pdf",
  "media_type": "document",
  "caption": "Here's the quarterly report"
}

​
Using the Universal Endpoint for Groups

You can also use the newer universal endpoint for group messages: 
POST /send/{accountId}
Headers:
  x-api-key: your_api_key
  x-api-secret: your_api_secret
  Content-Type: application/json

Body:
{
  "from": "+14155552671",
  "thread_id": "group-thread-id-123",
  "service": "whatsapp",
  "type": "group",
  "content": {
    "type": "media",
    "media_url": "https://example.com/videos/demo.mp4",
    "media_type": "video",
    "caption": "Product demo video for the team"
  }
}

​
Important Notes for Group Media Messages

  • For group messages, you need a valid thread_id instead of a to number.
  • The caption field is optional. You can send media without a caption if desired.
  • The same media type and size restrictions apply as with individual messages:
    • Images: Generally up to 5MB
    • Videos: Generally up to 16MB
    • Audio: Generally up to 16MB
    • Documents: Generally up to 100MB
  • The agent must be a member of the group before sending messages.

Authorizations

​
X-API-Key
string
header
required
​
X-API-Secret
string
header
required

Headers

​
X-API-Key
string
required
​
X-API-Secret
string
required

Path Parameters

​
accountId
string
required

Body

application/json
​
content
string
required

Message body text

​
from
string
required

Sender phone number

​
thread_id
string
required

ID of the chat thread

​
service
enum<string>
required

Messaging service to use

Available options:
whatsapp,
telegram
​
attachment_uri
string

Optional file/media attachment

Response

Message sent successfully

​
chat_group_id
string
​
from
string
​
body
string
​
status
enum<string>
Available options:
queued,
sent
​
date_created
string<date-time>