VEvercel
Messages

Send Message (Streaming)

Changed on

Sends a new message to an existing chat and returns a Server-Sent Events stream. Include designMode to apply element-scoped design edits; message may be omitted when edits are provided. Events include the initial assistant-message snapshot, content chunk deltas, final usage, and a closing message snapshot. The response is text/event-stream; each event is data: <JSON>\n\n where the JSON conforms to MessageStreamEvent. If the stream disconnects before the final event, reconnect with POST /chats/{chatId}/resume instead of sending the message again.

post/chats/{chatId}/messages/stream

Request

  • Base URL
    https://api.v0.dev/v2
  • URL
    https://api.v0.dev/v2/chats/{chatId}/messages/stream
  • Auth
    HTTP bearer

Path parameters

chatIdstring required

The unique identifier of the chat.

Request body

messagestring

The prompt or instruction to send to the model. May be omitted when designMode contains edits.

systemPromptstring

System-level context for the chat, such as frameworks or development environment details.

mcpServerIdsstring[]

MCP server IDs to enable. When omitted, uses default enabled servers.

Response

A single Server-Sent Events payload emitted by the streaming send-message endpoint. Each SSE event is data: <JSON>\n\n where the JSON conforms to one of the union members.

Changes

  • 467d24b4c224Revision changes
    • breaking

      removed the enum value v0-max of the request property / (media type: application/json)

    • breaking

      removed the enum value v0-max of the request property / (media type: application/x-www-form-urlencoded)

    • breaking

      removed the enum value v0-max of the request property / (media type: multipart/form-data)

    • breaking

      removed the enum value v0-max-fast of the request property / (media type: application/json)

    • breaking

      removed the enum value v0-max-fast of the request property / (media type: application/x-www-form-urlencoded)

    • breaking

      removed the enum value v0-max-fast of the request property / (media type: multipart/form-data)

    • breaking

      removed the enum value v0-mini of the request property / (media type: application/json)

    • breaking

      removed the enum value v0-mini of the request property / (media type: application/x-www-form-urlencoded)

    • breaking

      removed the enum value v0-mini of the request property / (media type: multipart/form-data)

    • breaking

      removed the enum value v0-pro of the request property / (media type: application/json)

    • breaking

      removed the enum value v0-pro of the request property / (media type: application/x-www-form-urlencoded)

    • breaking

      removed the enum value v0-pro of the request property / (media type: multipart/form-data)

    • breaking

      the / request property type changed from string to no type (media type: application/json)

    • info

      added subschema #1 subschema #2 to the / request property anyOf list (media type: application/json)

    • info

      added subschema #1 subschema #2 to the / request property anyOf list (media type: application/x-www-form-urlencoded)

    • info

      added subschema #1 subschema #2 to the / request property anyOf list (media type: multipart/form-data)

    • info

      the / request property type was generalized from string to no type (media type: application/x-www-form-urlencoded)

    • info

      the / request property type was generalized from string to no type (media type: multipart/form-data)

  • 0765e9bbdaf1Revision changes
    • info

      added the non-success response with the status