GPT Image 2.5 Sunburst
GPT Image 2.5, Sunburst build: denser detail and more in-frame text, faster to render, up to 4K.
First request
from openai import OpenAI
client = OpenAI(
base_url="https://api.altrouter.ai/v1",
api_key="ar-...",
)
img = client.images.generate(
model="gpt-image-2.5-sunburst",
prompt="a red fox in the snow",
)
print(img.data[0].url)import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://api.altrouter.ai/v1",
apiKey: process.env.ALTROUTER_API_KEY, // ar-...
});
const img = await client.images.generate({
model: "gpt-image-2.5-sunburst",
prompt: "a red fox in the snow",
});
console.log(img.data[0].url);curl https://api.altrouter.ai/v1/images/generations \
-H "Authorization: Bearer ar-..." \
-H "Content-Type: application/json" \
-d '{
"model": "gpt-image-2.5-sunburst",
"prompt": "a red fox in the snow"
}'The interface is OpenAI-compatible: in existing code only the base_url, the key and the model id change — nothing else.
GPT Image 2.5 Sunburst against its price neighbours
| Model | Price | Unit | Discount | |
|---|---|---|---|---|
| Seedream 4.5ByteDance | $0.040 | image | — | Open |
| FLUX.1 Kontext ProBlack Forest | $0.041 | image | — | Open |
| GPT Image 2.5OpenAI | $0.042 | image | — | Open |
| GPT Image 2.5 FlareOpenAI | $0.042 | image | — | Open |
| GPT Image 2.5 Sunburstthis pageOpenAI | $0.042 | image | — |
Prices and parameters come from the same catalog as the price above; this is not a benchmark, it is comparable billing terms.
Limits
Pricing is flat — $0.042 per image, regardless of prompt length. Allowed aspect_ratio values: auto, 1:1, 3:2, 2:3, 4:3, 3:4, 16:9, 9:16, 21:9.
There is no subscription: every successful request is billed at the price above, and a failed one is not billed at all. There is no markup over the vendor's official price. No OpenAI account of your own is needed: requests go to api.altrouter.ai and we make the upstream call.
Rate limiting is shared across models and counted per key: 600 requests per minute by default, and a 429 with retry-after: 60 above it. An individual key can get its own limit and a spending cap per day, week, month or lifetime in the dashboard.
When to pick GPT Image 2.5 Sunburst, and when a neighbour
The cheaper neighbour is FLUX.1 Kontext Pro: $0.041 per image against $0.042 for GPT Image 2.5 Sunburst. On the same volume the bill comes out 1× smaller. It is the sensible pick where the task is repetitive and high-volume — labelling, classification, short templated answers — the kind of work where quality is bounded by the prompt rather than the model.
The dearer neighbour is GPT Image 2.5: $0.042 per image. On catalog parameters it offers the same capabilities and the same order of context, so the premium is only justified if GPT Image 2.5 Sunburst falls short on your own task.
Guessing is more expensive than checking: the table above is prices and parameters, not a benchmark, and it cannot tell you which model does better on your own prompt. Switching costs one line — the model id in the request changes, the base_url and the key stay — so running both on your own data takes minutes.
OpenAI-compatible image generation endpoint. The result is re-hosted on our CDN and returned as a URL.
/v1/images/generations