# OpenAI GPT-5.5 API

> GPT-5.5 is an OpenAI flagship reasoning model with text and image input, made available in the API in April 2026 and described by OpenAI as built for complex professional work. OpenAI positions it for writing and debugging code, online research, data analysis, creating documents and spreadsheets, and operating software across tools until a task is done. It succeeds GPT-5.4 at similar per-token latency, and a pinned snapshot dated 2026-04-23 is available for fixed-version workloads.

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

## Facts

- Provider: OpenAI
- Type: Language model
- Model ID: `openai/gpt-5.5`
- Price: $5 per 1M input tokens, $30 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",
  "input": "Hello",
  "max_output_tokens": 2048
}'
```

## FAQ

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

Create a SandBase API key, then send requests with the model ID "openai/gpt-5.5" 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 cost?

$5 per 1M input tokens and $30 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?

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

### How does OpenAI GPT-5.5 score on benchmarks?

OpenAI GPT-5.5 scores 38.4 on the Artificial Analysis Intelligence Index (v4.3), ranking #26 of 83 models on SandBase; Coding Index 74.9, Agentic Index 36.4. Source: Artificial Analysis, measured as GPT-5.5 (Xhigh).

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

OpenAI GPT-5.5 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 and the other models in the catalog; you do not need to sign up with OpenAI separately.