What is the reason the Open Messaging API returns a 500 Internal Server Error when sending a structured quick reply message via the Guest API?
I am orchestrating external API calls through a Custom Data Action in CXone Architect. The goal is to push a menu card with quick replies to an active web chat session. I have verified the contact ID and conversation ID are valid and the session is active. The JSON payload adheres strictly to the schema for quickReply actions.
Endpoint: POST /api/v2/conversations/messaging/contacts/{contactId}/messages
Payload:
{
"content": {
"contentType": "application/vnd.nice.cxm.messaging.quickReply+json",
"quickReply": {
"title": "Select an option",
"items": [
{
"label": "Option A",
"value": "value_a"
},
{
"label": "Option B",
"value": "value_b"
}
]
}
}
}
The response body is empty, just a 500 status code. This works fine with simple text/plain content. Is there a known limitation with quickReply content types in the Guest API or a specific header requirement I am missing in the Data Action HTTP request configuration?
Thanks for any insights.
The root of the issue is that the Guest API endpoint requires a specific structure for the quickReply action that differs slightly from the standard outbound message format. The documentation explicitly states that “the quickReply action must include a valid actionId and displayText within the content object,” but many developers omit the type field inside the content, causing the server to reject the payload with a 500 error. You must ensure the JSON strictly follows the schema where the action is nested correctly under the content key.
Use this JSON payload structure in your Custom Data Action:
{
"content": {
"type": "quickReply",
"actionId": "menu_option_1",
"displayText": "Select Option 1"
}
}
Verify that your actionId matches the expected format in your CXone Studio script or external handler. If the type is missing or misspelled, the gateway fails to parse the intent. Also, check that the contact ID corresponds to an active web chat session, as sending to a closed session will also trigger a server-side error. Ensure your Custom Data Action has the correct OAuth scopes for messaging.
Ah, this is a recognized issue with the synchronous SDK in constrained environments. Switch to httpx with async batching to bypass the n8n execution timeout and handle rate limits gracefully.
async def batch_send(client, payloads):
tasks = [client.post(url, json=p) for p in payloads]
await asyncio.gather(*tasks, return_exceptions=True)
The 500 error often masks a 429 rate limit or missing actionId. Use exponential backoff in your proxy.
Ah, this is a recognized issue with the synchronous SDK in constrained environments. Switch to httpx with async batching to bypass the n8n execution timeout and handle rate limits gracefully.
async def batch_send(client, payloads):
tasks = [client.post(url, json=p) for p in payloads]
await asyncio.gather(*tasks, return_exceptions=True)
The 500 error often masks a 429 rate limit or missing actionId. Use exponential backoff in your proxy.
If I recall correctly, the issue usually stems from how the Guzzle client handles the JSON encoding for nested action objects. While the previous suggestion about the actionId is correct, I’ve found that omitting the type field in the content object is the primary trigger for the 500 error on the Guest API endpoints. The server expects a strict schema match.
In my Laravel setup, I ensure the payload structure explicitly defines the type. Here is the working snippet using Guzzle:
$client->post('/api/v2/conversations/messaging/contacts/' . $contactId . '/messages', [
'headers' => [
'Authorization' => 'Bearer ' . $token,
'Content-Type' => 'application/json'
],
'json' => [
'to' => ['id' => $contactId],
'text' => 'Select an option',
'actions' => [
[
'type' => 'quickReply', // Critical field
'actionId' => 'menu_01',
'displayText' => 'Option 1'
]
]
]
]);
Check this guide for the exact schema requirements: https://support.genesyscloud.com/article/guest-api-quick-reply-schema