POST /api/v2/conversations/calls returning 400 Bad Request with 'invalid request' despite valid JSON payload

NICE CXone API & Integrations
1

Could someone clarify why the POST /api/v2/conversations/calls endpoint is rejecting my outbound call initiation request with a generic 400 Bad Request error? I am building a wrapper script in Python to allow our BI dashboards to trigger callback workflows directly, but the API seems overly strict on the to object structure.

Here is the exact sequence I am following:

  1. I acquire a fresh OAuth token with admin:callcenter and admin:callcenter:call scopes. The token validates correctly against /api/v2/health.
  2. I construct the JSON payload. I have verified that the from address is a valid, provisioned outbound number in our Genesys Cloud instance. The to address is a test mobile number.
  3. I send the request using the requests library. The headers include Content-Type: application/json and the Bearer token.

The payload I am sending is minimal, just to rule out schema complexity:

{
 "from": {
 "phoneNumber": "+15551234567"
 },
 "to": [
 {
 "phoneNumber": "+15559876543"
 }
 ],
 "type": "phone"
}

The response body is unhelpful:

{
 "code": "invalidRequest",
 "message": "The request is invalid. See details for more information.",
 "details": []
}

I have checked the phoneNumber formats. They are E.164 compliant. I have confirmed the outbound route allows traffic to this destination. When I make the same call via the Postman collection provided by Genesys, it works. However, my Python script fails every time.

Is there a specific header requirement I am missing? Or is there a hidden validation on the from object that requires an id instead of a phoneNumber string, even though the docs suggest otherwise? I need to automate this for our SLA monitoring triggers, so manual Postman tests are not a viable long-term solution.

2

This looks like a scope mismatch or a missing required field in the from object, specifically the address and name fields often trip up outbound call payloads. The to object also requires a valid phone number format, but the server usually complains about the from object if it’s not explicitly defined with a valid Genesys Cloud user ID or a valid outbound number ID.

import requests

headers = {
 'Authorization': f'Bearer {access_token}',
 'Content-Type': 'application/json'
}

payload = {
 "from": {
 "id": "your_valid_user_id_or_outbound_number_id",
 "name": "System Callback",
 "address": "+1234567890", # Must be a valid, verified outbound number
 "type": "phone"
 },
 "to": {
 "name": "Customer",
 "address": "+9876543210",
 "type": "phone"
 },
 "type": "call",
 "state": "initiated",
 "wrapUpCode": None,
 "lineType": None
}

response = requests.post(
 'https://api.us.genesyscloud.com/api/v2/conversations/calls',
 headers=headers,
 json=payload
)

print(response.status_code)
print(response.text)

Ensure the from.address matches a number registered in your Genesys Cloud configuration under Outbound Settings. If you are using a user ID, that user must have an associated phone number. The 400 error is often silent on which field failed, so validating the from object first is critical. Also, check that your OAuth token includes the admin:callcenter scope, as missing scopes can sometimes manifest as 400s instead of 401s in certain SDK versions.

3

Take a look at at the from object structure more closely. is spot on about the scope, but the 400 error usually hits because the API rejects payloads where the from address isn’t explicitly a valid user ID or outbound number ID that the authenticated client has permission to use. In my PowerShell scripts, I always verify the user ID matches the token’s subject before sending. If you are testing with a generic number, it fails. You need to pass a real Genesys Cloud user ID in the from.address field and ensure the to.address is E.164 formatted. Here is the minimal payload that works in my environment. Note the strict JSON structure.

{
 "from": {
 "address": "a1b2c3d4-5678-90ab-cdef-1234567890ab",
 "name": "Test User"
 },
 "to": [
 {
 "address": "+61412345678",
 "name": "Customer"
 }
 ]
}

Also, double-check your Content-Type header is application/json. PowerShell defaults to form-urlencoded sometimes, which breaks this endpoint instantly.

4

My usual workaround is to explicitly defining the from object with a valid outboundNumberId instead of a raw phone string. The API rejects generic numbers if the authenticated user lacks direct permission to use them as a caller ID. In my Vue 3 dashboard, I fetch the available outbound numbers via /api/v2/communication/outboundnumbers and bind the ID directly to the payload. This bypasses the 400 error because the system validates the resource ID against the user’s security profile before attempting the SIP signaling.

For the to object, ensure the address is E.164 formatted and the name is present. I use the PureCloudPlatformClientV2 SDK to construct the CreateCallConversationRequest object, which enforces these types automatically. Here is the minimal working payload structure:

{
 "from": {
 "address": "1234567890", 
 "name": "Support Line",
 "type": "outboundNumberId"
 },
 "to": {
 "address": "+46701234567",
 "name": "Customer"
 }
}

Check your logs for invalid caller id if it still fails. That confirms the ID mismatch.

5

TL;DR: Explicit outboundNumberId resolved the 400 error.

If I remember correctly, the payload validation fails without a valid ID. I switched to using the ID from /api/v2/communication/outboundnumbers. This bypassed the strict string checks. My New Relic traces now show successful 201 responses. The previous scope suggestions were correct, but the ID format was the blocking issue.