# OpenAI GPT-5.5 Pro API

> GPT-5.5 Pro is a separate OpenAI model in the GPT-5.5 family that uses more compute to think harder and give consistently better answers, according to OpenAI. It is intended for tough, high-stakes problems where answer quality matters more than speed, and some requests can take several minutes to finish. Choose it over standard GPT-5.5 when reliability on difficult reasoning, coding or analysis justifies the extra latency; OpenAI serves it for multi-turn and batch API requests.

Source: https://www.sandbase.ai/models/openai/gpt-5.5-pro
API reference: https://www.sandbase.ai/models/openai/gpt-5.5-pro/docs

## Facts

- Provider: OpenAI
- Type: Language model
- Model ID: `openai/gpt-5.5-pro`
- Price: $30 per 1M input tokens, $180 per 1M output tokens
- Context window: 1.1M tokens, up to 128K output tokens
- Capabilities: chat, vision, reasoning, structured output, function calling
- Billing: pay per use from one SandBase balance; no provider account or subscription needed

## Call it

- Responses API: `POST https://api.sandbase.ai/v1/responses`
- Chat Completions API: `POST https://api.sandbase.ai/v1/chat/completions`

```bash
curl -X POST https://api.sandbase.ai/v1/responses \
  -H "Authorization: Bearer $SANDBASE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "openai/gpt-5.5-pro",
  "input": "Hello",
  "max_output_tokens": 2048
}'
```

## FAQ

### How do I call OpenAI GPT-5.5 Pro through SandBase?

Create a SandBase API key, then send requests with the model ID "openai/gpt-5.5-pro" to Responses API (/v1/responses) or Chat Completions API (/v1/chat/completions) at https://api.sandbase.ai. The request examples on this page show the exact payload.

### How much does OpenAI GPT-5.5 Pro cost?

$30 per 1M input tokens and $180 per 1M output tokens, billed per request from your SandBase balance. Discounts, when available, are shown in the pricing on this page.

### What is the context window of OpenAI GPT-5.5 Pro?

1.1M tokens of context, with up to 128K output tokens per response.

### Which features does OpenAI GPT-5.5 Pro support?

OpenAI GPT-5.5 Pro supports vision (image input), reasoning, function calling, structured output. See Specifications above for the full list.

### Do I need a separate OpenAI account?

No. One SandBase API key and balance gives you access to OpenAI GPT-5.5 Pro and the other models in the catalog; you do not need to sign up with OpenAI separately.