CXone Contact API 400 on Salesforce ETL push

NICE CXone API & Integrations
1

Problem

The outbound list sync breaks when the Python script pushes Salesforce leads to the CXone Contact API. It’s not holding the payload structure correctly in the Contact Configuration.

Code

payload = {"contactListId": "abc-123", "contacts": [{"phone": "+15550199", "externalId": "sf_884"}]}
requests.post(f"{base_url}/api/v2/contact-center/outbound/contacts", json=payload, headers=headers)

Error

The endpoint returns a 400 Bad Request complaining about missing mandatory fields, even though the WEM dashboard shows the Queue Configuration is active.

Question

How do I fix the JSON mapping without rewriting the whole ETL loop.

2 
curl -X POST https://api.cxone.net/api/v1/outbound/contacts \
 -H "Authorization: Bearer $TOKEN" \
 -H "Content-Type: application/json" \
 -d '{
"contactListId": "abc-123-def",
"contacts": [{
"phoneNumber": "+15551234567",
"externalId": "sf_884",
"firstName": "Jane",
"lastName": "Doe"
}]
}'

Outbound list sync fails. Python script pushes Salesforce leads to the Contact API. Payload structure misaligned in Contact Configuration.

Returns 400 Bad Request. Endpoint requires lead data nested under the contacts array. Root-level flattening triggers schema validation errors. Verify the service account has the outbound-data-api:write permission. Insufficient permissions cause silent failures.

Routing via a local mock or direct production hit? Consider using the CXone Provisioning API to validate your contact list configuration. Manual overrides to the list definition can introduce payload mismatches. Check your automation state.