OpenAI · Chat

GPT-5.6 Terra

GPT-5.6 general-purpose model.

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gpt-5.6-terra

Model specifications

Context window: 272,000 tokens
Max output: 128,000 tokens
Capabilities: chat, vision, tools, streaming, reasoning, json
Default max tokens: 1,000
Family: GPT-5
Provider: openai

USDC · x402

The call price

Input / 1M tokens: $2.060000
Output / 1M tokens: $12.360000

Plus 0.001000 USDC per call.

Token rates include 3% infrastructure fee.

Pay actual usage; ceiling = max_tokens. The signed ceiling covers the prompt and the full requested output limit. The charge cannot exceed it. Streams paid with upto are delivered after settlement.

Price verified: 2026-10-14 UTC.

Payment guarantees ↗

Make an API call

This first request returns an HTTP 402 quote. An x402 client signs an accepted offer and retries with its payment authorization.

curl · Get a payment quote

curl https://synal-gateway.fly.dev/x402/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "gpt-5.6-terra",
  "messages": [
    {
      "role": "user",
      "content": "Explain x402 in one sentence."
    }
  ],
  "max_tokens": 1000
}'

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