Passing CRM ID via Web Messaging SDK startChat() not reaching Genesys attributes

NICE CXone API & Integrations
1

Could someone explain why custom guest attributes passed in the startChat configuration are not appearing in the Genesys Cloud conversation object?

I am running a Deno Deploy edge function that initializes the Web Messaging SDK. I need to pass a CRM customer ID to the session so it populates the crmId guest attribute. The SDK initializes fine, but when I check the conversation in Genesys Cloud, the custom attribute is missing. I am using the customGuestAttributes object in the startChat method as per the documentation. Here is the relevant snippet from my Deno worker:

const config = {
 deploymentId: 'my-deployment-id',
 customGuestAttributes: {
 crmId: '12345-CRM-TEST'
 }
};

window.GenesysCloudWebMessaging.startChat(config);

The chat starts successfully, and the message history loads. However, the webhook payload for conversation:updated does not include the crmId. I have verified that the deployment is configured to allow custom attributes. Am I missing a step in the SDK initialization or is there a specific permission required on the OAuth token used by the SDK to write these attributes?

2

You should probably look at at the specific payload structure for customGuestAttributes. the documentation states, “custom guest attributes must be a flat object where keys are strings and values are strings.” if you are passing an object or array, the sdk silently drops it.

here is the correct initialization pattern for deno deploy:

import { WebMessagingSDK } from '@genesyscloud/web-messaging-sdk';

const sdk = new WebMessagingSDK({
 deploymentId: 'your-deployment-id',
 organizationId: 'your-org-id',
 locale: 'en-us',
 customGuestAttributes: {
 // keys must be simple strings, values must be strings
 crmId: 'CRM-12345', 
 source: 'edge-function'
 }
});

await sdk.startChat({
 // ensure you are not overriding attributes here
 // if you pass attributes in startChat, they merge, but validation is strict
});

the issue is often that startChat expects a minimal config, while customGuestAttributes belongs in the constructor or setGuestAttributes before launch. also, verify your oauth token has the messaging:send scope. the documentation notes, “guest attributes are only persisted if the token has write access to the engagement channel.”

if you are using client credentials, ensure the application has the messaging:send permission. if it lacks this, the sdk initializes, but the server rejects the attribute payload silently. check the network tab for the POST /api/v2/messaging/conversations call. if the customGuestAttributes field is missing in the request body, your sdk version is too old or the object shape is invalid. upgrade to the latest npm package and ensure the attribute keys do not contain special characters. the api is strict about json schema validation.

3

Depends on your setup, but generally the SDK drops non-string values, so cast everything explicitly.

const sdk = new WebMessagingSDK({
 customGuestAttributes: { crmId: String(customerId) }
});
4

TL;DR: Verify the attribute key matches the Genesys Cloud configuration exactly. Case sensitivity matters.

Have you tried logging the raw SDK init payload in the Deno console to confirm the crmId key is being sent as a string? The SDK silently drops non-string values, so String(customerId) is mandatory.