Streaming

Set stream to true and CrossModel returns incremental results as Server-Sent Events. The event format differs by protocol, but the client approach is the same: read chunk by chunk, append the text, and handle the end and error events.

Chat Completions

curl https://api.crossmodel.ai/v1/chat/completions \
  -H "Authorization: Bearer $CROSSMODEL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "deepseek/deepseek-v4-pro",
    "messages": [{ "role": "user", "content": "Tell me a short story" }],
    "stream": true
  }'

Chat Completions returns chat.completion.chunk events. Concatenate choices[0].delta.content from each chunk to rebuild the full reply.

Responses

The Responses streaming endpoint uses event objects with a type field, for example:

Event	Notes
`response.created`	The response begins.
`response.output_text.delta`	A text increment.
`response.function_call_arguments.delta`	A function-arguments increment.
`response.completed`	The response ends.

Messages

The Anthropic Messages streaming endpoint uses the Anthropic event format, such as message_start, content_block_delta, message_delta, and message_stop.

Error handling

A streaming response can still error after the connection is open. The client must handle error events — don't just wait for [DONE] or the end event:

Chat Completions: you may receive a data: chunk with an error field.
Responses: you may receive event: error.
Messages: you may receive an Anthropic error event.

When a stream fails partway through, don't append the result of an automatic retry onto the output you already have. The safer move is to mark the generation as failed and start a fresh, complete request.