Updating participant attributes on live Genesys Cloud call fails with 409

I’m trying to push some dynamic context data from our internal CRM into a live voice conversation using the Genesys Cloud Conversations API. The goal is simple: update a participant attribute so the agent sees the customer’s loyalty tier in the sidebar while the call is active.

Here’s the setup:

  • Platform: Genesys Cloud ()
  • API Endpoint: PATCH /api/v2/conversations/voice/{conversationId}/participants/{participantId}
  • SDK: Python genesyscloud v2

I get the conversation ID from the inbound webhook. I wait for the participant to be in connected state. Then I send the PATCH request with the following payload:

{
 "attributes": {
 "loyalty_tier": "gold",
 "last_order_id": "99283"
 }
}

The response is consistently a 409 Conflict. The error body says:

{
 "errors": [
 {
 "message": "The request conflicts with the current state of the resource.",
 "code": "CONFLICT"
 }
 ]
}

I’ve checked the docs. It mentions that you need to include the version field in the request body to handle optimistic locking. I tried adding the current version of the participant (fetched via a GET request just before the PATCH), but it still fails. Same 409.

I also tried fetching the full participant object, modifying the attributes, and sending the whole thing back. Still no luck. The version increments every time I read it, which makes sense, but updating it seems impossible.

Is there a specific header I’m missing? Or is this endpoint actually read-only for active calls? I know I can use the put endpoint for creating participants, but that’s not what I need here. I just want to update existing metadata.

Anyone else hit this wall? I’ve been staring at the Swagger spec for an hour and it’s not clicking.