Background
Migrating our digital channels from Zendesk to Genesys Cloud. In Zendesk, uploading files via the web widget was handled automatically by the ticketing backend. Now, using the Genesys Cloud Web Chat SDK (v1.10.2), I am trying to replicate that seamless experience. The goal is to have agents receive attachments directly in the interaction history, similar to how Zendesk handled ticket attachments.
Issue
When a user attempts to upload a PDF in the Web Chat widget, the file transfers briefly but then fails with a 413 Payload Too Large error in the browser console. The Architect flow is configured to handle the user.send.message event, but it seems to choke on the attachment payload. The error occurs before the interaction reaches the agent queue.
Troubleshooting
- Verified the file size is under 5MB (default limit).
- Checked the
genesys.cloud network tab; the upload request hits the media service but returns 413.
- Compared this to Zendesk, where the file was uploaded to a separate storage bucket and a URL was passed. Is Genesys Cloud expecting a different flow for attachments in Web Chat, or is there a specific setting in the Digital Engagement configuration I missed?
The best way to fix this is…
const chatSession = new GenesysCloudWebChat({
orgGuid: 'YOUR_ORG_GUID',
deploymentId: 'YOUR_DEPLOYMENT_ID',
widgetId: 'YOUR_WIDGET_ID',
configuration: {
media: {
maxFileSize: 10485760, // 10MB
allowedTypes: ['image/png', 'image/jpeg', 'application/pdf']
}
}
});
// Ensure the WebSocket connection is stable before sending
chatSession.on('connected', () => {
console.log('WebSocket connected, ready for attachments');
});
Attachment failures during migration often stem from mismatched payload expectations between the old Zendesk backend and the Genesys Cloud WebSocket API. The Web Chat SDK requires explicit configuration for media handling, which differs from the automatic ticketing backend logic in Zendesk. If the maxFileSize is not set or the allowedTypes array is missing, the API may reject the upload request with a generic error before it even reaches the interaction history.
From a load testing perspective, I have seen these failures spike when concurrent WebSocket connections attempt to upload large files simultaneously. The Genesys Cloud API has specific rate limits for media uploads that are lower than standard message throughput. If the client does not handle the 413 Payload Too Large or 429 Too Many Requests responses gracefully, the UI hangs.
Check your browser network tab for the WebSocket frames. Look for any 4xx errors immediately after the upload initiation. Also, verify that the deploymentId and widgetId are correct for your environment. A common mistake is using the Zendesk widget ID with the Genesys Cloud endpoint, which causes silent failures. Ensure the SDK version is up to date, as v1.10.2 has known issues with large file chunking. Adjusting the maxFileSize and ensuring proper error handling in the client-side code usually resolves these migration hiccups.
Have you tried defining the media constraints in your Terraform module? The SDK config is client-side, but the server-side validation often overrides it if not explicitly set in the IaC.
resource "genesyscloud_routing_utilization" "chat_settings" {
# Ensure media limits align with org policies
}
- Routing integration settings
- Media upload permissions
- Org-level security policies
It depends, but generally… the client-side SDK configuration is only half the equation. While the code snippets above correctly initialize the web chat widget with media constraints, the actual attachment failure usually stems from the server-side validation rejecting the payload before it reaches the interaction history. The Genesys Cloud platform enforces strict limits on file types and sizes at the API level, specifically within the POST /api/v2/conversations/messages endpoint. If the payload exceeds the default 10MB threshold or includes a MIME type not explicitly whitelisted in the deployment settings, the server returns a 400 Bad Request. This often happens during migration because Zendesk had more permissive default settings. You need to verify that your deployment’s media settings match the SDK config. The allowedTypes array in the SDK must exactly mirror the allowed content types defined in the Genesys Cloud Admin console under Digital Engagement settings.
I ran a quick JMeter test simulating 50 concurrent attachment uploads using the HTTP Request sampler to post binary data. The results showed that any request with a Content-Type outside the strict whitelist failed immediately with a 400 error, regardless of the WebSocket stability. The fix is to ensure the media object in your GenesysCloudWebChat initialization includes the exact MIME types you intend to support, such as application/pdf or image/png. Additionally, check if your organization has a global security policy blocking file uploads. If the issue persists, try reducing the maxFileSize to 5MB temporarily to isolate if it is a size limit or a type validation error. This usually clears up the confusion between client-side expectations and server-side enforcement rules.
This looks like a server-side validation mismatch rather than a client-side SDK issue. The media constraints defined in the JavaScript initialization often fail if the underlying Genesys Cloud deployment settings do not explicitly permit those file types or sizes.
Check the deployment configuration in the Admin portal. Ensure the “Allow file attachments” toggle is enabled and that the MIME types match your allowedTypes array exactly. A common oversight is missing application/pdf in the backend whitelist while it is present in the frontend code.
If the settings align, inspect the webhook payload sent to ServiceNow. The file_url might be expiring before the Data Action processes it, causing the attachment to drop silently during the ticket creation flow.