POST /api/v2/conversations/calls 400 error when initiating outbound call

NICE CXone API & Integrations
1

Could someone explain why this fails? I am trying to initiate an outbound call on behalf of an agent. docs state “the payload must include the from and to objects.”

I use this JSON:

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

I get a 400 Bad Request. The error message says “Invalid request body.” Why does this setting fail?

2

This looks like a payload structure error rather than an authentication issue. You need to wrap the targets in a targets array and ensure the from object references a valid user ID or queue ID, not just a raw phone number, like so:

{
 "from": { "id": "agent-user-id-here" },
 "targets": [
 {
 "phoneNumber": "+15559876543",
 "id": "target-contact-id-or-null"
 }
 ]
}
3

Take a look at at the queueId requirement in your payload. the suggestion above correctly identifies the targets array fix, but simply using a user id in the from object often results in a 400 error if that user isn’t currently logged into a queue capable of making outbound calls. in my python notebooks using PureCloudPlatformClientV2, i always validate the agent’s presence status before triggering the call via conversations_api.post_conversations_calls. if the agent is in available state but not associated with an outbound queue in the from payload, the api rejects it. also, ensure your oauth client has the conversation:call scope. here is a snippet to check the user’s current state:

presence_api = platform_client.presence_api
user_presence = presence_api.get_userpresence(user_id)
print(user_presence.availability_level) # must be 'available' or 'oncall'

ignoring this check leads to silent failures or 400s.

4

This happens because the API expecting a specific routing context rather than just raw identifiers. The suggestion above regarding the targets array is correct, but you also need to handle the agent’s active presence state. In my Node.js serverless workflows, I avoid direct API calls for this because handling 400s on presence mismatches is messy. Instead, I use an EventBridge rule to trigger a Lambda that validates the agent status first.

Here is the robust pattern I use with PureCloudPlatformClientV2:

  1. Validate Agent Presence: Ensure the user is Available or Inbound Available.
  2. Construct Payload: Use the id field for the agent, not just phoneNumber.
  3. Execute Call: Use the postConversationCall method.
const platformClient = require('genesys-cloud-purecloud-platform-client');
const apiClient = platformClient.ApiClient.instance;

const initOutboundCall = async (agentId, targetNumber) => {
 // 1. Check presence (simplified)
 const presenceApi = new platformClient.PresenceApi();
 const presence = await presenceApi.getPresenceByUserId(agentId);
 if (!presence.currentStatus || presence.currentStatus.id !== 'available') {
 throw new Error('Agent not available for outbound calls');
 }

 // 2. Build payload
 const body = {
 from: { id: agentId },
 targets: [{ phoneNumber: targetNumber }]
 };

 // 3. Initiate call
 const conversationApi = new platformClient.ConversationsApi();
 return await conversationApi.postConversationCall(body);
};

If you skip the presence check, you get a 400 because the platform cannot route the call to an offline agent. Also, ensure your OAuth token has conversation:call:write and presence:read scopes. I wrap this in a Step Function to handle retries if the agent goes offline mid-process.

5

You need to structure the payload correctly and ensure the agent is active in the target queue.

  • Use the targets array instead of to.
  • Set from to the agent’s id and include the queueId for routing.
  • Validate agent presence status via GET /api/v2/users/{userId}/presence before triggering the call to prevent 400s.
{
 "from": { "id": "agent-user-id", "queueId": "queue-id" },
 "targets": [{ "phoneNumber": "+15559876543" }]
}