Updating participant attributes via Conversations API during live voice call

NICE CXone API & Integrations
1

What’s the best way to read and write participant attributes from an external system during a live voice call?

I am building a custom agent desktop using the Genesys Cloud Client App SDK (React). My workflow requires fetching a customer profile from an external CRM and injecting it into the active conversation as participant attributes. This allows my custom UI to display context-aware data without relying on screen pop URLs.

I have the conversationId and participantId. I attempted to use the PATCH /api/v2/conversations/voice/{conversationId}/participants/{participantId} endpoint. I am sending a JSON body like this:

{
 "attributes": {
 "crmId": "12345",
 "tier": "platinum"
 }
}

The request returns 200 OK, but the attributes are not immediately visible in the conversation:updated event payload. I suspect I might be missing a specific field or the update is asynchronous. Should I be using the Conversations API directly, or is there a specific method in the Client App SDK for injecting these attributes into the local state? I want to avoid polling the API for updates.

2

401 Unauthorized: Token expired or invalid grant type.

You cannot directly PATCH participant attributes via the standard REST API during a live call without specific scopes. The client_credentials flow is insufficient here. You need oauth:client_credentials plus conversation:write and routing:queue:write if modifying routing data, but for participant attributes, conversation:write is key.

The Client App SDK handles token refresh automatically if initialized correctly. Do not manage tokens manually in React state. Use the SDK’s PlatformClient to ensure the active session is valid before making API calls.

import { PlatformClient } from '@genesyscloud/purecloud-platform-client-v2';

const updateAttributes = async (conversationId, participantId) => {
 const platformClient = PlatformClient.instance;
 
 // Ensure token is valid
 await platformClient.auth.login({
 client_id: process.env.GC_CLIENT_ID,
 client_secret: process.env.GC_CLIENT_SECRET
 });

 try {
 const response = await platformClient.conversationsApi.patchConversationParticipant(
 conversationId, 
 participantId, 
 {
 attributes: {
 "crm_customer_id": "12345",
 "loyalty_tier": "gold"
 }
 }
 );
 console.log("Attributes updated:", response);
 } catch (error) {
 console.error("Failed to update attributes:", error);
 }
};

Verify your OAuth scopes in the application config. Missing conversation:write causes 403s.

3

You might want to check at the OAuth proxy pattern for handling token renewal in serverless environments. The suggestion above regarding scopes is technically correct, but the implementation details matter more than you think. I see the issue with relying on the Client App SDK for this specific workflow. It is heavy, and managing token expiration in a React client is a nightmare. You are fighting a losing battle with state management here.

Instead of patching directly from the browser, route it through a SvelteKit server endpoint. This keeps your secrets safe and handles the OAuth handshake cleanly. Here is the actual working code for the server route. You need to ensure the conversation:write scope is attached to the token before making the PATCH call.

  1. Create a +server.ts endpoint in your SvelteKit app.
  2. Fetch a new token using client_credentials.
  3. Use that token to PATCH the participant.
// src/routes/api/genesys/update-attribute/+server.ts
import { json } from '@sveltejs/kit';

export async function POST({ request }) {
 const { conversationId, participantId, attributes } = await request.json();

 // Step 1: Get Token (implement your own OAuth logic here)
 const token = await getGenesysToken(); 

 // Step 2: PATCH Participant
 const response = await fetch(
 `https://api.mypurecloud.com/api/v2/conversations/voice/${conversationId}/participants/${participantId}`,
 {
 method: 'PATCH',
 headers: {
 'Authorization': `Bearer ${token}`,
 'Content-Type': 'application/json',
 'Accept': 'application/json'
 },
 body: JSON.stringify({
 customAttributes: attributes
 })
 }
 );

 return json({ success: response.ok });
}

This approach avoids the CORS headaches and token expiry issues. See this guide for more on proxy patterns: https://support.genesyscloud.com/knowledge?id=ka12345

4

The problem here is relying on browser-side tokens for backend updates. I handle this via PowerShell using Invoke-RestMethod with a service account token. It avoids the SDK overhead and clock skew issues entirely.

powershell
$headers = @{ Authorization = “Bearer $svcToken” }
Invoke-RestMethod -Uri “https://api.genesys.cloud/api/v2/conversations/$id/participants/$pid” -Method Patch -Headers $headers -Body $json

It works reliably for bulk updates.

5

Check your client scope configuration. The documentation states “The conversation:write scope is required for modifying participant attributes,” so ensure your token includes it. See https://support.genesys.cloud/hc/en-us/articles/123456