ServiceNow Data Action 400 Error: Nested JSON Payload Serialization Failure

Can anyone clarify the correct schema structure for passing complex nested objects from a Genesys Cloud Data Action to a ServiceNow REST API endpoint? We are currently deploying a ticket automation flow that triggers upon specific IVR menu selections. The Data Action is configured to hit the /api/now/table/incident endpoint, but it consistently returns a 400 Bad Request with the message “Invalid JSON format” when the work_notes field contains a nested array of interaction logs.

The payload construction within the Data Action looks structurally sound based on the ServiceNow documentation, yet the serialization seems to break during the transmission from the GC environment. The request body being sent is:

{
 "short_description": "IVR Route: Billing Inquiry",
 "caller_id": "{{contact.email}}",
 "work_notes": [
 {
 "timestamp": "{{flow.trigger.timestamp}}",
 "action": "Routing to Billing Queue"
 }
 ]
}

Interestingly, if we flatten the work_notes into a simple string concatenation, the 400 error disappears and the ticket creates successfully. This suggests the issue lies specifically in how the Data Action serializes the array object before the HTTP POST request is executed. We have verified that the ServiceNow table field type is correctly set to Multiple Lines and accepts JSON strings, so the backend schema is not the bottleneck.

Is there a known limitation in the Genesys Cloud Data Action connector regarding nested JSON serialization for ServiceNow targets? Or should we be implementing a custom transformation step within the Architect flow prior to invoking the Data Action to ensure the payload is strictly stringified? The standard webhook payload format works for simple key-value pairs, but this nested structure is failing validation on the GC side before it even reaches the ServiceNow instance. We need a reliable method to pass structured interaction history without resorting to manual string manipulation in the flow logic.

I’d suggest checking out at the raw json payload before it hits the service now endpoint. from a load testing perspective, the 400 error usually means the serialization layer in the data action is dropping fields or creating malformed brackets when nesting occurs. i ran a similar test with jmeter yesterday where the work_notes object had too many nested levels. the genesys cloud data action editor sometimes strips quotes or escapes characters incorrectly when the payload gets complex.

try simplifying the nested object first. instead of sending a full nested json structure for work_notes, flatten it or send it as a simple string. if you must nest, check the data action configuration. ensure the content-type header is explicitly set to application/json. i noticed in my jmeter scripts that if the header is missing, service now defaults to application/x-www-form-urlencoded which breaks the parser immediately.

here is a sample payload structure that worked for me in a low-concurrency test:

{
 "short_description": "test incident",
 "work_notes": "note content here"
}

if you need nested data, wrap it in quotes properly:

{
 "custom_field": "{\"key\": \"value\"}"
}

also, check the service now system properties for glide.restapi.request.max_size. if your jmeter test sends large payloads, you might hit the limit before the json parser even runs. i set mine to 1mb to avoid this. run a single thread in jmeter first to isolate the payload format issue before ramping up concurrency. the 400 error is almost always a schema mismatch, not a rate limit issue. fix the json structure first, then worry about the throughput.