How does streaming token generation architecture work in ChatGPT APIs?

Streaming sends tokens to the client as they are generated instead of waiting for full response completion.

Streaming architecture in ChatGPT exposes partial outputs token-by-token as they are generated by the transformer. Instead of waiting for full sequence completion, the server flushes tokens over a persistent connection (e.g., WebSocket or HTTP chunked transfer).

Internally, the decoder loop produces one token at a time using autoregressive inference. Each token is immediately serialized and sent to the client while KV cache is maintained server-side for efficiency.

This significantly improves perceived latency and user experience, even though total compute time remains similar.