Models/OpenAI/GPT-5.6

OpenAI: GPT-5.6

Name: GPT-5.6
Brand: OpenAI
Price: 2.1252 USD
Availability: InStock

Textgpt-5.6

The refreshed GPT-5.6 workhorse: strong code, reasoning and tool calling, 400K context.

API docs

Playgroundgpt-5.6

Reasoning

Web search

Throughput195 tok/s

24hnow

Latency0.93 s

24hnow

Specifications

Authoropenai

ModalityText

Context400K tokens

Input$2.13/M tokens$2.50/M tokens

Output$12.75/M tokens$15.00/M tokens

Savings−15%

Capabilitiesreasoning, tool calling, image input

Quick start

from openai import OpenAI

client = OpenAI(
    base_url="https://api.altrouter.ai/v1",
    api_key="ar-...",
)

resp = client.chat.completions.create(
    model="gpt-5.6",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(resp.choices[0].message.content)

Same OpenAI-compatible endpoint — just swap base_url and key.

API

OpenAI-compatible chat completions endpoint, with SSE streaming.

POST/v1/chat/completions

Body parameters

modelstringrequired"gpt-5.6"

The model id.

messagesarrayrequired

The conversation: [{ role, content }].

streambooleandefault false

Stream the response over SSE.

reasoning_effortenumlow · medium · high · xhighdefault low

Thinking budget for reasoning models.

web_searchbooleandefault false

Server-side web search — answers with live data.

Structured fields (tools, response_format, stop and more) are in the full parameter reference.

Response

idstring

Completion id.

choicesarray

Completions. Each: index, message { role, content, reasoning_content, tool_calls }, finish_reason.

usageobject

Tokens: prompt_tokens, completion_tokens, total_tokens.

Example

cURLPythonJSON

curl https://api.altrouter.ai/v1/chat/completions \
  -H "Authorization: Bearer ar-..." \
  -H "Content-Type: application/json" \
  -d '{
  "model": "gpt-5.6",
  "messages": [
    {
      "role": "user",
      "content": "Hello!"
    }
  ],
  "reasoning_effort": "low"
}'

Errors

400Invalid request.

401Missing or invalid API key.

402Insufficient credits, or the key’s spending cap is exhausted.

404Model not found.

429Rate limit exceeded.