# gpt-5.6-terra — API, Pricing & Context Window | Vivgrid

> Source: https://vivgrid.com/docs/models/gpt-5.6-terra

gpt-5.6-terra on Vivgrid: OpenAI's balanced gpt-5.6 model with a 1.05M-token context window, strong coding performance, and geo-distributed acceleration.

`gpt-5.6-terra` is the balanced model in OpenAI's gpt-5.6 family and the successor to `gpt-5.4`, delivering most of `gpt-5.6-sol`'s coding and reasoning quality at half the price. Its **1.05M-token context window** makes it a strong default for production agents.

On Vivgrid, `gpt-5.6-terra` is served through a single OpenAI-compatible endpoint with **geo-distributed acceleration across AMER and EMEA**, reachable with the same unified key as the rest of the catalog.

## Specifications

| Field | Value |
| --- | --- |
| Provider | OpenAI |
| Model ID | `gpt-5.6-terra` |
| Best for | Coding |
| Available on | Chat Completions, Vibe coding |
| Context window | 1,050,000 tokens |
| Max output | 128,000 tokens |
| Modalities | Text, Image |
| Tool / function calling | Yes |
| Knowledge cutoff | 2026-03 |
| Acceleration | Geo-distributed — AMER, EMEA |

## Pricing

Pricing in USD per 1M tokens, matching the provider's rates.

| Input | Cached input | Output |
| --- | --- | --- |
| $2.50 | $0.25 | $15.00 |

### What one request costs

The rates above applied to a 20K-token prompt with a 2K-token reply — a typical single agent turn, small enough that every request is billed at the base rate.

| Request | Cost |
| --- | --- |
| Cold prompt, nothing cached | $0.0800 |
| Warm prompt, 90% of the input served from cache | $0.0395 |


Requests beyond **272K input tokens** are billed at the long-context rate: $5.00 input / $0.50 cached input / $22.50 output per 1M tokens.

## API surfaces

The Vivgrid Console catalogs `gpt-5.6-terra` on 2 surfaces, all behind the same API key. The endpoint shown is the one the Console previews for that surface.

| Surface | Primary endpoint | Use it for |
| --- | --- | --- |
| Chat Completions | `/chat/completions` | Agent projects, where Vivgrid injects the model, system prompt and tools server-side, and Model API calls that name the model per request. |
| Vibe coding | `/chat/completions` | Coding CLIs and IDE agents that drive the model themselves — point the tool at Vivgrid and keep your own loop. |

## Quick start

Get an API key from the Vivgrid Console (https://console.vivgrid.com), then call `gpt-5.6-terra` directly.

```bash
curl https://api.vivgrid.com/v1/chat/completions \
  -H "Authorization: Bearer $VIVGRID_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.6-terra",
    "messages": [
      { "role": "user", "content": "Say hello in English, Chinese and Spanish." }
    ],
    "stream": true
  }'
```


## Ideal use cases

- Production coding agents balancing quality, speed, and cost
- Whole-repository analysis within a 1.05M-token context
- High-volume tool-calling workflows on Chat Completions
- Teams standardizing on one model across coding and agent tasks

## Related models

- [gpt-6.1-sol](/docs/models/gpt-6.1-sol) — the balanced gpt-6 model at a lower price
- [gpt-5.6-sol](/docs/models/gpt-5.6-sol) — the flagship gpt-5.6 model
- [gpt-5.6-luna](/docs/models/gpt-5.6-luna) — the fast, low-cost gpt-5.6 model