GPT-5.6 Terra Pro API

openai/gpt-5.6-terra-pro
Extended-reasoning variant of GPT-5.6 Terra — OpenAI's mid-tier model between Sol and Luna — built for tasks where accuracy matters more than response speed, with a 1M-token context window and support for image input.
Context
1.1M tokens
Input
$2.7508 / 1M tokens
Output
$16.5048 / 1M tokens
Released
Jul 9, 2026

How to use GPT-5.6 Terra Pro API

Install any OpenAI-compatible SDK, point it at api.aimlapi.com/v1, and set the model to openai/gpt-5.6-terra-pro.
import requests

r = requests.post(
    "https://api.aimlapi.com/v1/chat/completions",
    headers={"Authorization": "Bearer " + AIMLAPI_KEY},
    json={
      "model": "openai/gpt-5.6-terra-pro",
      "messages": [
        {
          "role": "user",
          "content": "Hello!"
        }
      ]
    },
)
print(r.json())
const r = await fetch("https://api.aimlapi.com/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.AIMLAPI_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "model": "openai/gpt-5.6-terra-pro",
    "messages": [
      {
        "role": "user",
        "content": "Hello!"
      }
    ]
  }),
});
console.log(await r.json());
curl -X POST https://api.aimlapi.com/v1/chat/completions \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"openai/gpt-5.6-terra-pro","messages":[{"role":"user","content":"Hello!"}]}'

OpenAI-compatible — swap the base URL and it works with your existing SDK.

GPT-5.6 Terra Pro API Pricing

TypePrice
Input
$2.7508 / 1M tokens
Output
$16.5048 / 1M tokens
Cached input
$0.27508 / 1M tokens

Prompts with more than 272K input tokens are billed at 2x input and 1.5x output for the full request, and cache writes are billed at 1.25x the uncached input token rate.

GPT-5.6 Terra Pro Benchmarks

BenchmarkScoreWhat it measuresSourceRetrieved
GPQA Diamond
92.9%
Google-proof graduate science questions (hardest subset)SourceSeptember 21, 2026
Humanity's Last Exam
22.8%
Expert-level questions across many domainsSourceSeptember 21, 2026
MMMU
83.2%
College-level multimodal understanding + reasoningSourceSeptember 21, 2026
AIME 2025
44.7%
Competition mathematics (AIME), 2025SourceSeptember 21, 2026
MMLU-Pro
90.0%
Multi-discipline knowledge + reasoning (harder MMLU)SourceSeptember 21, 2026

GPT-5.6 Terra Pro vs other models

ModelInputOutputContextBest for
$2.7508 / 1M tokens
$16.5048 / 1M tokens
1.1M tokens
Agentic workflows and structured output
$0.0975 / 1M tokens
$0.325 / 1M tokens
1M tokens
Coding + agentic reasoning
$0.82524 / 1M tokens
$8.2524 / 1M tokens
1.04M tokens
Reasoning + agents
$0.41262 / 1M tokens
$3.4385 / 1M tokens
1M tokens
Reasoning + agents

Frequently asked questions

GPT-5.6 Terra Pro has a 1,050,000 tokens context window and can return up to 128,000 tokens.

GPT-5.6 Terra Pro takes image, text as input and returns text.

Use openai/gpt-5.6-terra-pro as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.

GPT-5.6 Terra Pro became available on July 9, 2026.

GPT-5.6 Terra Pro is priced at input $2.7508 / 1M tokens, output $16.5048 / 1M tokens, cached input $0.27508 / 1M tokens.

Yes, GPT-5.6 Terra Pro can stream responses as they are generated.

Yes, GPT-5.6 Terra Pro accepts image input alongside text.

GPT-5.6 Terra Pro was built by OpenAI.

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