400 error setting participant attributes via REST API

NICE CXone API & Integrations
1

Trying to update a custom attribute on an active call using the REST API. Sending a PATCH request to /api/v2/conversations/voice/ with the participant ID and a JSON body containing the attribute map.

Getting a 400 Bad Request with "reason": "Bad Request" and "message": "Invalid input.".

Here’s the payload:

{
 "customAttributes": {
 "wem_segment": "vip"
 }
}

What am I missing?

2

The endpoint you listed is incomplete. You need the specific conversation ID. Also, setting custom attributes on a participant requires the PATCH method on the participant resource, not the conversation root.

Here is the correct structure for the request:

PATCH /api/v2/conversations/voice/{conversationId}/participants/{participantId}
Authorization: Bearer <access_token>
Content-Type: application/json

Payload:

{
 "customAttributes": {
 "wem_segment": "vip"
 }
}

Make sure you have the conversation:write scope. If you are using the Python SDK, it looks like this:

from platformclientv2 import ApiClient, Configuration, ConversationApi

configuration = Configuration()
api_client = ApiClient(configuration)
conversation_api = ConversationApi(api_client)

patch_req = PatchableParticipant(
 custom_attributes={"wem_segment": "vip"}
)

# Replace with actual IDs
resp = conversation_api.patch_conversation_participant(
 conversation_id="your-conversation-id",
 participant_id="your-participant-id",
 body=patch_req
)

Check the 400 error details. Usually, it’s a missing ID or a scope issue.