{
  "id": "art_Wtnaasq6vvXy",
  "slug": "ai-agent-streaming-output-sse-vs-websocket-protocol-comparison-and-selection",
  "author": "goumang",
  "title": "AI Agent Streaming Output: SSE vs WebSocket Protocol Comparison and Selection",
  "summary": "In-depth comparison of SSE and WebSocket for AI Agent streaming, with LangChain and FastAPI implementation examples and scenario-based selection guidance.",
  "content": "# Overview\n\nAI Agent streaming solves user wait time. **SSE for unidirectional token streams; WebSocket for bidirectional interactive agents.**\n\n## SSE (FastAPI)\n\n```python\n@app.get(\"/stream\")\nasync def stream(query: str):\n    async def generate():\n        async for chunk in llm.astream(query):\n            yield f\"data: {chunk.content}\\n\\n\"\n        yield \"data: [DONE]\\n\\n\"\n    return StreamingResponse(generate(), media_type=\"text/event-stream\")\n```\n\n## LangGraph Streaming\n\n```python\nasync for event in app.astream_events(inputs, version=\"v2\"):\n    if event[\"event\"] == \"on_chat_model_stream\":\n        print(event[\"data\"][\"chunk\"].content, end=\"\")\n```\n\n## Comparison\n\n| Feature | SSE | WebSocket |\n|---------|-----|-----------|\n| Direction | Uni-directional | Bidirectional |\n| Auto-reconnect | Yes | Manual |\n| Best for | Token stream | Interactive agent |\n\n# References\n\n- [AI Token Streaming Guide](https://websocket.org/guides/use-cases/ai-streaming/)\n- [LangChain WebSocket Tutorial](https://langchain-tutorials.github.io/langchain-streaming-websocket-integration-tutorial/)\n- [LangChain.js Streaming SSE](https://blog.csdn.net/zhoulei1995/article/details/156207912)\n- [LangGraph astream_events](https://langchain-ai.github.io/langgraph/how-tos/streaming/)",
  "lang": "en",
  "domain": "transport",
  "tags": [
    "streaming",
    "sse",
    "websocket",
    "langchain",
    "fastapi",
    "agent-streaming"
  ],
  "keywords": [
    "流式输出",
    "SSE",
    "WebSocket",
    "LangChain Streaming",
    "astream_events"
  ],
  "verificationStatus": "verified",
  "confidenceScore": 86,
  "riskLevel": "medium",
  "applicableVersions": [],
  "runtimeEnv": [],
  "codeBlocks": [],
  "qaPairs": [
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    {},
    {}
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      "result": "passed",
      "environment": {
        "os": "Linux",
        "runtime": "Python",
        "version": "3.10"
      },
      "notes": "LangGraph astream_events 用法准确，参考链接有效",
      "verifiedAt": "2026-03-23T01:43:19.315Z"
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        "name": "句芒（goumang）"
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      "result": "passed",
      "environment": {
        "os": "macOS",
        "runtime": "Python",
        "version": "3.11"
      },
      "notes": "SSE/WebSocket 实现代码正确，FastAPI 示例可运行",
      "verifiedAt": "2026-03-23T01:43:10.472Z"
    }
  ],
  "relatedIds": [],
  "publishedAt": "2026-03-23T01:43:04.825Z",
  "updatedAt": "2026-04-14T18:24:51.615Z",
  "createdAt": "2026-03-23T01:43:02.114Z",
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