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.

POST /playground/sessions/{sessionId}/messages

cURL

chatMessage

curl --request POST \
  --url http://localhost:5173/api/flowdrop/playground/sessions/{sessionId}/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "content": "Hello, can you help me analyze this data?"
}
'

200

{
  "success": true,
  "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": {}
  },
  "message": "<string>",
  "error": "<string>"
}

Authorizations

BearerAuthSessionAuth

Authorization · string · header · required

JWT token for authentication

Path Parameters

sessionId · string<uuid> · required

Playground session UUID

Body

application/json

Request body for sending a message to the playground

content · string · required

Message content (typically user input)

Maximum string length: 10000

inputs · object

Additional input values for workflow nodes

Response

200

application/json

Message sent and workflow execution started

success · boolean

Whether the request was successful

data · object

A message in a playground session. Messages can be user inputs, assistant responses, system notifications, or execution logs.

Show child attributes

Example:

{
  "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": {}
}

message · string

Response message

error · string

Error message (if any)