更新日: 2026-06-06

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Responses API Overview

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Current framing

• If you need inspectable reasoning output, prefer /v1/responses
• If you need OpenAI-style web search, prefer /v1/responses
• If you only need ordinary chat or want to keep an existing integration, /v1/chat/completions is still fine

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Responses API vs Chat Completions API

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Smallest useful example

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.crazyrouter.com/v1"
)

response = client.responses.create(
    model="gpt-5.5",
    input="Explain what a REST API is in one sentence."
)

print(response.output_text)

{
  "object": "response",
  "output": [
    {
      "type": "message"
    }
  ]
}

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When to prefer Responses

• You need gpt-5.5 reasoning summaries
• You need to verify whether the model actually triggered web_search_call
• You want richer SSE events

• GPT-5 Thinking Mode
• Responses Web Search
• Responses Function Calling

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When to keep Chat Completions

• You already have a stable Chat Completions integration
• You only care about the final answer, not the reasoning item
• You are integrating Claude, Gemini, or other OpenAI-compatible models