Send a message to the playground session

Send a user message or trigger workflow execution with inputs. This starts or continues the conversation in the playground. The message is created with status "pending" and processing begins immediately (synchronously) or is queued (asynchronously) based on the session's execution mode. The response returns immediately with the message entity, allowing clients to poll the message status endpoint to track processing progress. Messages are processed in sequence order within a session to ensure proper conversation flow. If a previous message is not yet complete, the request will be rejected with a conflict error.

curl -X POST "https://example.com/playground/sessions/497f6eca-6276-4993-bfeb-53cbbbba6f08/messages" \  -H "Content-Type: application/json" \  -d '{    "content": "Hello, can you help me analyze this data?"  }'

{  "success": true,  "message": "string",  "error": "string",  "data": {    "id": "be4d854d-d6b3-4242-b2ea-0008b2e059bd",    "sessionId": "fe5304ea-f069-433f-b0bf-945975c0b806",    "role": "user",    "content": "Hello. How are you?",    "timestamp": "2026-01-19T10:03:32+01:00",    "status": "completed",    "sequenceNumber": 1,    "parentMessageId": null,    "nodeId": null,    "metadata": {}  }}