> ## Documentation Index
> Fetch the complete documentation index at: https://docs.crazyrouter.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Create Response

> Responses API basics verified against Crazyrouter production on 2026-03-23

> Last updated: 2026-06-06

# Create Response

```
POST /v1/responses
```

As of March 23, 2026, Crazyrouter production has verified:

* `gpt-5.5` returns `object: "response"`
* basic text requests currently return `output` items of type `message`
* streaming requests consistently expose `response.created`, `response.in_progress`, `response.output_item.added`, `response.content_part.added`, and `response.output_text.delta`

<Note>
  Claude does not currently support `POST /v1/responses`. Use `POST /v1/messages` or `POST /v1/chat/completions` for Claude instead.
</Note>

***

## Basic Request

```bash theme={null}
curl https://api.crazyrouter.com/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gpt-5.5",
    "input": "Explain what an API is in one sentence."
  }'
```

Observed production response shape:

```json theme={null}
{
  "object": "response",
  "model": "gpt-5.5",
  "output": [
    {
      "type": "message"
    }
  ]
}
```

***

## Streaming Request

```bash theme={null}
curl https://api.crazyrouter.com/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gpt-5.5",
    "input": "Say hello in one sentence.",
    "stream": true
  }'
```

The production streaming probe on 2026-03-23 observed this opening event sequence:

```text theme={null}
event: response.created
event: response.in_progress
event: response.output_item.added
event: response.content_part.added
event: response.output_text.delta
```

So the safest current consumer strategy is:

1. accumulate text from `response.output_text.delta`
2. treat `response.completed` or stream termination as the completion signal

***

## Current Recommendation

* Start new GPT text integrations with `gpt-5.5` on `/v1/responses`
* For tool use, continue with [Responses Function Calling](/chat/responses/function-calling)
* For live web access, continue with [Responses Web Search](/chat/responses/web-search)
* For visible reasoning markers, continue with [GPT-5 Thinking](/chat/responses/gpt5-thinking)