Fusion API: toman pricing and code
openrouter/fusion
Fusion example: summarising a document
The example is picked from this model's own capabilities. Drop in your key and it runs as is.
from openai import OpenAI
client = OpenAI(base_url="https://api.uttapen.ir/v1", api_key="sk-up-…")
stream = client.chat.completions.create(
model="openrouter/fusion",
messages=[{"role": "user", "content": "Summarise this text in three sentences:
\"This year's budget act makes three main changes…\""}],
stream=True,
)
for chunk in stream:
print(chunk.choices[0].delta.content or "", end="", flush=True)import OpenAI from "openai";
const client = new OpenAI({ baseURL: "https://api.uttapen.ir/v1", apiKey: "sk-up-…" });
const stream = await client.chat.completions.create({
model: "openrouter/fusion",
messages: [{ role: "user", content: "Summarise this text in three sentences:
\"This year's budget act makes three main changes…\"" }],
stream: true,
});
for await (const chunk of stream) process.stdout.write(chunk.choices[0]?.delta?.content ?? "");curl https://api.uttapen.ir/v1/chat/completions \
-H "Authorization: Bearer sk-up-…" \
-H "Content-Type: application/json" \
-d '{
"model": "openrouter/fusion",
"messages": [{"role": "user", "content": "Summarise this text in three sentences: \"This year's budget act makes three main changes…\""}],
"stream": true
}'What is Fusion good for?
Fusion is one of OpenRouter's models. Put "openrouter/fusion" in the model field and the rest of your code stays as it is. Fusion keeps 1,000,000 tokens in view at once, and that number is what caps the conversation history in your product. It has no fixed price: the destination model is chosen per request, and you are charged exactly what the model that answered actually cost.
This one handles text only. If you need function calling or image understanding, pick another model from the same catalogue — swapping is a one-line change.
Its nearest relative in the catalogue is "openrouter/bodybuilder", and choosing between those two is where most people hesitate. The context windows differ too: 1,000,000 against 128,000 tokens.
OpenRouter has 6 models in our catalogue. It does not support include_reasoning, max_tokens, reasoning, response_format, which most models here do, so test before switching if your code relies on them. By context size the nearest option from another provider is Nova 2 Lite at 1,000,000 tokens.
What to use it for: automatic routing when you would rather not pick a model yourself, analysing a long document or codebase in one request.
Fusion turns your prompt into a small multi-model deliberation. A panel of expert models (see below) analyzes your prompt in parallel with web search and web fetch enabled, then a...
Frequently asked
- How do I call Fusion from Iran?
- Sign up with your mobile number, top the wallet up in toman, create an API key, then in the official OpenAI SDK point base_url at https://api.uttapen.ir/v1 and set model to "openrouter/fusion". Nothing else in your code changes.
- What does Fusion cost in toman?
- This model has no fixed price: the cost depends on the model that answered the request, and that exact amount is what leaves your wallet.
- How much input does Fusion take?
- Up to 1,000,000 tokens per request, roughly 750k words. Cap the answer length yourself with max_tokens.
- Can I stream Fusion's output?
- Yes — with stream=true you get SSE events as the tokens are produced. This model has no tool calling and no image input, so pick a different one if you need either.