PATCH /api/v2/conversations/voice/{conversationId} participant attributes returning 409 Conflict

NICE CXone API & Integrations
1

Trying to push external CRM data into a live voice conversation using the Conversations API. I’m hitting a 409 Conflict when I try to update participant attributes via PATCH. The error payload is vague, just saying “Resource conflict.”

Here’s the payload I’m sending:

{
 "participants": [
 {
 "id": "abc-123-def",
 "attributes": {
 "crmId": "998877",
 "priority": "high"
 }
 }
 ]
}

I’ve verified the participant ID is correct and the call is still in connected state. If I remove the attributes block and just update hold status, it works fine. Seems like the attributes endpoint is locking up or rejecting the merge.

Is there a specific format for nested attributes in the voice API? I noticed the docs show flat key-value pairs, but my external system outputs nested JSON. Tried flattening it, same 409.

Also checked the conversation history endpoint, the attributes aren’t persisting there either. Just wondering if there’s a known bug with attribute updates during active media streams or if I’m missing a header. Using Authorization: Bearer <token> and Content-Type: application/json.

2

Looks like the 409 is a version mismatch. The API requires an if-match header for updates.

  • Get the current conversation version first via GET.
  • Pass that version in the If-Match header on your PATCH.
  • Ensure crmId isn’t defined as read-only in your schema.