Streaming.
Streaming returns a model's tokens incrementally as they're generated rather than waiting for the complete response to finish.
Streaming is a response delivery method where large language models output tokens one by one as they generate them, rather than waiting to complete the entire response before sending it to the user. This approach dramatically improves the perceived responsiveness of AI applications by allowing users to see text appearing in real-time, similar to watching someone type. Streaming is particularly valuable for longer responses where waiting for completion would create noticeable delays and poor user experience.
The streaming process works by establishing a persistent connection between the client and server, typically using Server-Sent Events (SSE) or WebSocket protocols. As the model generates each token through its inference process, it immediately transmits that token to the client application, which displays it to the user. This differs from traditional request-response patterns where the entire output is buffered server-side before transmission. The implementation requires careful handling of connection management, error states, and graceful termination when generation completes.
Streaming significantly reduces time-to-first-token perception and keeps users engaged during longer generations, but introduces complexity in application design and error handling. Developers must account for partial responses, connection interruptions, and the inability to modify earlier parts of streamed content. While streaming improves user experience, it doesn't actually reduce the total generation time or computational cost—it simply redistributes when users receive the information. Some applications may prefer non-streaming responses for batch processing or when the complete response is needed before taking action.
Related terms.
- Time to First TokenTime to First Token (TTFT) measures the latency from sending a request to receiving the first streamed token, primarily determined by the prefill phase.
- LatencyThe delay between sending a request to an LLM and receiving the first token of the response, often measured as Time to First Token (TTFT).
- InferenceThe process of running a trained AI model to generate outputs — what happens when you send a prompt and receive a response.
- Tokens per SecondTokens per second measures how quickly an LLM generates text during inference, serving as the primary throughput metric for comparing model speed.