Streaming API Responses

Real-time token delivery via Server-Sent Events

🔑 Key Concepts

SSE vs WebSocket — SSE is simpler (HTTP), one-directional (server→client), auto-reconnects. Perfect for LLM streaming.
Implementation — StreamingResponse with media_type='text/event-stream'. Yield 'data: {token}\n\n' for each chunk.
Client side — EventSource API in JavaScript. Onmessage callback fires for each token. Easy to implement.
Error handling — Send 'data: [ERROR] message\n\n' on failure. Client reconnects automatically with SSE.

💡 Practice: Try implementing each concept yourself before moving on. Reading about RAG and building RAG are very different things.