# OpenAI GPT-5.1 API

> GPT-5.1 is OpenAI's GPT-5 series flagship released in November 2025 for coding and agentic tasks, with text and image input and text output. It adapts how long it thinks to task complexity, spending fewer tokens on simple requests and staying persistent on hard ones, and adds a no-reasoning mode that behaves like a low-latency non-reasoning model with strong tool calling. It succeeds GPT-5 as the full-size general-purpose option in that line.

Source: https://www.sandbase.ai/models/openai/gpt-5.1
API reference: https://www.sandbase.ai/models/openai/gpt-5.1/docs

## Facts

- Provider: OpenAI
- Type: Language model
- Model ID: `openai/gpt-5.1`
- Price: $1.25 per 1M input tokens, $10 per 1M output tokens
- Context window: 400K 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-5.1",
  "input": "Hello",
  "max_output_tokens": 2048
}'
```

## FAQ

### How do I call OpenAI GPT-5.1 through SandBase?

Create a SandBase API key, then send requests with the model ID "openai/gpt-5.1" 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-5.1 cost?

$1.25 per 1M input tokens and $10 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-5.1?

400K tokens of context, with up to 128K output tokens per response.

### How does OpenAI GPT-5.1 score on benchmarks?

OpenAI GPT-5.1 scores 24.7 on the Artificial Analysis Intelligence Index (v4.3), ranking #51 of 83 models on SandBase; Coding Index 49.4. Source: Artificial Analysis, measured as GPT-5.1 (High).

### Which features does OpenAI GPT-5.1 support?

OpenAI GPT-5.1 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-5.1 and the other models in the catalog; you do not need to sign up with OpenAI separately.