Webhook delivery failing with 5xx — implementing a dead letter queue for retries

Quick question about handling webhook failures in CXone. My endpoint returns 500 intermittently, and CXone stops retrying after a few attempts. I want to implement a dead letter queue pattern. Is there a way to configure the webhook subscription via the /api/v2/webhooks API to forward failed payloads to a separate S3 bucket or Lambda for manual retry? I tried setting the retryCount in the JSON payload but it seems ignored. Here is my current config: { “eventTypes”: [“conversation.analyzed”], “retryCount”: 5 }. Any ideas?

def handler(event, context):
 # Write payload to S3 DLQ if target returns 5xx
 s3.put_object(Bucket='dlq-bucket', Key='failed.json', Body=json.dumps(event))

This ensures no conversation data is lost during transient endpoint failures.

The way I solve this is by bypassing the webhook subscription layer entirely for critical data pipelines. Instead, use an intermediate AWS Lambda as the primary webhook target. This Lambda acts as a durable buffer. If the downstream consumer fails, the Lambda explicitly writes the event body to an S3 bucket or SQS queue. This mirrors the pattern seen in Twilio Functions where you control the failure path directly rather than hoping the platform retries correctly. The webhook subscription simply points to arn:aws:lambda:eu-west-1:.... Inside the handler, validate the HTTP status code from the downstream call. If status >= 500, invoke boto3.client('s3').put_object.

Warning: Ensure your Lambda timeout exceeds the downstream processing time to avoid premature termination.

{
 "eventTypes": ["conversation:updated"],
 "url": "https://your-lambda-url",
 "retryConfig": {
 "maxRetries": 5,
 "backoff": "exponential"
 }
}

If I remember correctly, the retryCount field you mentioned is deprecated. The retryConfig object handles internal retries, but for a true dead letter queue, you must return 200 OK from your Lambda to stop CXone retries, then handle the downstream failure and S3 write within the Lambda function itself.

Error: 400 Bad Request. Message: Invalid webhook configuration.

The platform does not support native dead-letter queue forwarding to external endpoints.

The solution is to route the webhook to a single AWS Lambda function. Then, inside the Lambda, implement your own retry logic with an exponential backoff. If the downstream processor fails, write the payload to an SQS queue or S3 bucket as your dead letter. This mirrors the Terraform state management pattern where you handle drift locally rather than expecting the provider to fix it automatically.

{
 "eventTypes": ["conversation:updated"],
 "url": "https://your-lambda-url",
 "retryConfig": {
 "maxRetries": 0,
 "backoff": "linear"
 }
}