Architect Flow Timeout on High Concurrent WebSocket Connections

My current config is completely failing… I am running a load test against a simple Architect flow designed to handle concurrent voice interactions. The setup involves a single IVR entry point that routes calls to a queue. Under low load, everything functions correctly. However, when I increase the JMeter thread count to simulate 500 concurrent sessions, the system starts failing.

The specific issue is a WebSocket disconnect followed by an HTTP 408 Request Timeout. This happens consistently after the first 200 connections are established. The remaining connections hang for exactly 30 seconds before dropping. I have verified that the Edge cluster has sufficient capacity and the queue agents are available. The problem seems to be related to how Architect handles the initial handshake or session creation under burst traffic.

I am using the Genesys Cloud API v2 endpoints for the initial call setup. The JMeter script sends a POST request to the /api/v2/interactions/calls endpoint. Here is the error response captured from the JMeter listener:

{
 "code": "requestTimedOut",
 "message": "The request timed out before the server could respond."
}

I have checked the Architect flow logs, and I do not see any explicit errors there. The calls simply disappear from the active session list. I suspect this might be a rate-limiting issue on the WebSocket layer or a configuration setting in the IVR that restricts concurrent processing threads.

Has anyone seen this behavior before? I am aware of the general API rate limits, but this feels like a specific Architect capacity bottleneck. I am on the Genesys Cloud platform, region US-East. I need to understand if there is a specific setting in the Architect flow or the IVR configuration that I need to adjust to handle this load. Any insights on WebSocket keep-alive settings or Architect thread limits would be helpful.

Take a look at at how your ServiceNow Data Action is handling the webhook payloads for these high-concurrency events, as the timeout often stems from the downstream system failing to acknowledge the Genesys Cloud event within the expected window rather than the Architect flow itself. When 500 concurrent sessions trigger simultaneous screen pops or ticket updates, the ServiceNow REST API can become a bottleneck if the connection pool is not sized correctly or if the payload transformation logic is too heavy. The documentation for Genesys Cloud webhooks specifies a retry mechanism, but if ServiceNow returns a non-2xx status code or times out before Genesys Cloud receives a confirmation, the flow might hang waiting for the action to complete, leading to the 408 error you are seeing. Try implementing a lightweight acknowledgment strategy in your ServiceNow script include. Instead of processing the full ticket creation synchronously within the webhook handler, push the payload to an asynchronous queue or use a background job. This ensures Genesys Cloud receives a 200 OK response immediately, keeping the Architect flow state machine moving. Additionally, check your ServiceNow instance’s inbound traffic rules and consider increasing the timeout value in the Genesys Cloud Data Action configuration to allow for slight delays in high-load scenarios. The webhook payload structure should remain minimal, containing only the necessary correlation IDs like the conversation ID and agent ID. If you are using a custom script to parse the JSON, ensure it is optimized for speed. A common fix is to add a try-catch block that logs errors to a separate table without blocking the main execution thread. This decouples the critical path of the voice interaction from the potentially slower ServiceNow record creation process. Monitor the ServiceNow logs for any slow scripts during the load test to identify specific bottlenecks.

The simplest way to resolve this is to isolate the bottleneck from the Architect flow logic entirely. While the suggestion above points to ServiceNow, 408 timeouts in Genesys Cloud usually indicate that the WebSocket handshake or the subsequent message queue is stalling due to resource contention, not just downstream API limits. When managing high-concurrency environments, especially with BYOC trunks, the SIP signaling load often overwhelms the default session timers before the application logic even runs.

Check the websocket.maxMessageSize and connectionTimeout settings in your deployment configuration. Increasing the keep-alive interval can prevent premature drops. Additionally, verify if your carrier-specific failover logic is triggering unnecessarily during peak load, which adds significant overhead to the SIP registration state. If the traffic is purely voice, consider offloading the initial wait time to a carrier-side announcement rather than holding the WebSocket open in the flow. This reduces the server-side session count significantly. Monitor the SIP INVITE success rate vs. the WebSocket disconnect rate to correlate the exact failure point.

This seems like a classic case of external endpoint latency cascading into the Architect flow’s internal timeout limits. When you push 500 concurrent sessions, the system isn’t just failing on the WebSocket handshake; it is likely timing out while waiting for a response from the downstream integration or data action. The 408 indicates the server closed the connection because the request took too long to process.

In our experience building AppFoundry integrations, this usually happens when the external service (like ServiceNow or a custom webhook) doesn’t respond within the Architect flow’s default wait time. The flow waits, the WebSocket connection sits idle, and eventually, the platform drops it to free up resources.

To mitigate this, you need to decouple the synchronous wait. Instead of having the Architect flow wait for the external API to complete, use an asynchronous pattern. Trigger the external event via a webhook or data action that returns immediately, then process the heavy lifting in the background.

Here is how you might structure the payload to ensure quick acknowledgment:

{
 "callId": "{{callId}}",
 "userId": "{{userId}}",
 "timestamp": "{{now}}"
}

Ensure your external endpoint returns a 202 Accepted status immediately upon receiving this payload. Do not wait for the database write or third-party API call to finish before responding to Genesys Cloud.

Additionally, review your OAuth token refresh strategy. High concurrency can sometimes trigger rapid token refreshes if the tokens are short-lived, adding unnecessary latency. Consider using a longer-lived token or caching the token securely in your application logic to avoid repeated authentication handshakes during peak load.

Check your external service logs for any queued requests. If they are backing up, you may need to scale your endpoint or implement a message queue like AWS SQS to buffer the incoming events from Genesys Cloud.