Send a chat message and stream the agent's response

Accepts a user message, stores it in the chat session, routes it to the specified agent, streams back the agent’s response, and automatically saves the assistant’s response when streaming completes. Use X-Stream-Mode header to control stream format: ‘text’ for simple text stream (default) or ‘uimessage’ for UI message stream with progress updates.

POST /chat-sessions/send-message

Send a chat message and stream the agent's response

cURL

curl --request POST \
  --url https://api.flipsidecrypto.xyz/public/v3/chat-sessions/send-message \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --header 'x-session-id: <x-session-id>' \
  --data '
{
  "messages": [
    null
  ],
  "agentId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "agentName": "<string>",
  "attachedFiles": [
    "<string>"
  ]
}
'

200

"<string>"

Authorizations

x-api-key · string · header · required

Headers

x-session-id · string<uuid> · required

The chat session ID

x-stream-mode · enum<string> · default: text

Stream mode: 'text' for simple text stream, 'uimessage' for UI message stream with custom data parts

Available options: text, uimessage

Body

application/json

messages · null[] · required

The UIMessages from the AI SDK representing the user's message

agentId · string<uuid>

The agent ID (UUID) to route this message to. Takes priority over agentName.

agentName · string

The agent name/ref to route this message to. Used as fallback when agentId is not provided.

attachedFiles · string[]

Filenames of org uploads attached to this message. When provided, the csv_upload skill is automatically added.

Response

200

text/event-stream

Message received and agent stream started successfully

Server-sent events stream of the agent's response