GPT-5.6 Terra
Save 90%Officialopenai/gpt-5.6-terra
Balanced GPT-5.6 quality and cost for production workloads.
- Context window
- 1.1M
- Max output
- 128K
- Input modalities
- text · image
- Output modalities
- text
- Capabilities
- Vision · Reasoning · Tool calling · Coding · Prompt cache · Paid cache writes · Strip Responses Summary Input
- Upstream release
- 2026-07-09
- RouteMux name
- openai/gpt-5.6-terra
Try GPT-5.6 Terra here
Tune the request, see the current price ceiling, and inspect the real response without leaving this model page.
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What is GPT-5.6 Terra
GPT-5.6 Terra is the middle of the GPT-5.6 line, and for most production traffic it is the one that should be running. It keeps everything structural about Sol — the 1.05M-token context window, vision input, tool calling, configurable reasoning, persisted reasoning, prompt caching — and asks $0.20 / $1.20 per 1M tokens against Sol's $0.40 / $2.00.
Through RouteMux that works out to $0.20 per 1M input tokens against OpenAI's $2, and $1.20 against $12 on output. Three protocols are available: OpenAI Chat Completions, OpenAI Responses, and Anthropic Messages.
The practical way to use the family is to default to Terra and escalate. Because all three models share the same context window and the same request shape, escalation is a one-line change, and you find out quickly whether a task actually needed Sol or just needed a better prompt.
GPT-5.6 Terra API pricing
Source: openai_x0.10 · Verified 2026-08-24
Fast $0.4 / $2.4 /M
Cache read $0.02/M · Cache write $0.25/M
| Tier | Input | Cache read | Cache write | Output |
|---|---|---|---|---|
| Standard ≤272K | $0.2 | $0.02 | $0.25 | $1.2 |
| Standard >272K | $0.4 | $0.04 | $0.5 | $1.8 |
| Priority ≤272K | $0.4 | $0.04 | $0.5 | $2.4 |
Estimate cost
Limited time20% extra Credits on your first top-up — up to 200 bonus Credits
Applies to your first top-up within 72 hours of signing up. Minimum $20, once per account.
Key capabilities
Same structure as Sol
1.05M context, vision, tools, reasoning controls and caching are identical — only price and depth differ.
Built for steady production load
Priced so that a high-traffic assistant or coding agent can run on it continuously rather than as a treat.
Escalation is one line
Moving a hard request up to Sol means changing the model string, nothing else.
Three protocols
OpenAI Chat, OpenAI Responses, and Anthropic Messages all route here.
Interface and protocols
Use any of these IDs to call this model via the API.
openai/gpt-5.6-terraReplace the ROUTEMUX_KEY placeholder with your API key. Create one →
from openai import OpenAI
client = OpenAI(
base_url="https://api.routemux.com/v1",
api_key="<ROUTEMUX_KEY>",
)
completion = client.chat.completions.create(
model="openai/gpt-5.6-terra",
messages=[{"role": "user", "content": "What is the meaning of life?"}],
)
print(completion.choices[0].message.content)Performance (last 30 days)
GPT-5.6 Terra FAQ
›What is GPT-5.6 Terra?
Balanced GPT-5.6 quality and cost for production workloads.
›How large is the context window of GPT-5.6 Terra?
GPT-5.6 Terra supports a context window of up to 1.1M tokens, with up to 128K output tokens per request.
›How much does the GPT-5.6 Terra API cost?
Through RouteMux, GPT-5.6 Terra costs $0.2 for input and $1.2 for output (USD per 1M tokens), below the official list price.
›How do I call GPT-5.6 Terra via API?
GPT-5.6 Terra is OpenAI-compatible: point your base URL at RouteMux and set the model field to openai/gpt-5.6-terra — no code changes needed.
›Which input and output modalities does GPT-5.6 Terra support?
GPT-5.6 Terra accepts text, image as input and produces text as output.
›When was GPT-5.6 Terra released?
GPT-5.6 Terra was released on July 9, 2026.
›When should I use Sol instead of Terra?
When the task is failing on Terra for reasoning reasons rather than prompt reasons. Both have the same context and tools, so context pressure is not the differentiator.
›Is the context window really the same as Sol's?
Yes — 1.05M tokens on both, with 128K max output.