Fugu Ultra v2

Not rated yet. Independent test results usually appear a few weeks after a model is released.

Benchmark data: Epoch AI, licensed CC BY 4.0

Companies that serve this model through an API: 1. Prices per million tokens, cheapest first.

Availability and prices come from OpenRouter’s public API and are refreshed daily. Uptime is the share of successful requests over the last 24 hours. Some providers run a compressed version of open models (fp8, int4), which is cheaper but can be slightly less accurate.

Call Fugu Ultra v2 through OpenRouter’s OpenAI-compatible API: create a key on openrouter.ai, then run one of these examples.

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "sakana/fugu-ultra-v2", "messages": [{"role": "user", "content": "Hello! What can you do?"}]}'

import os
from openai import OpenAI

client = OpenAI(base_url="https://openrouter.ai/api/v1", api_key=os.environ["OPENROUTER_API_KEY"])
reply = client.chat.completions.create(
    model="sakana/fugu-ultra-v2",
    messages=[{"role": "user", "content": "Hello! What can you do?"}],
)
print(reply.choices[0].message.content)

import OpenAI from "openai";

const client = new OpenAI({ baseURL: "https://openrouter.ai/api/v1", apiKey: process.env.OPENROUTER_API_KEY });
const reply = await client.chat.completions.create({
  model: "sakana/fugu-ultra-v2",
  messages: [{ role: "user", content: "Hello! What can you do?" }],
});
console.log(reply.choices[0].message.content);

The same code works with every model on this site: only the model ID changes. Many labs also offer their own API and SDK.

• 1,000 chat replies

  ≈ 500 tokens in, 300 out each
  $11.50
• Summarise a 100-page document

  ≈ 50,000 tokens in, 1,000 out
  $0.28
• An app with 10,000 requests a day for a month

  ≈ 1,000 tokens in, 400 out each
  $5,100

Cost calculator →

How much does Fugu Ultra v2 cost?

Fugu Ultra v2 costs $5 per million input tokens and $30 per million output tokens through the API. For example, 1,000 chat replies of about 500 tokens in and 300 out cost around $11.50.

What is the context window of Fugu Ultra v2?

Fugu Ultra v2 can read up to 1,000,000 tokens in one request, about 1,875 pages of text. It can write up to 128,000 tokens in a single answer.

Is Fugu Ultra v2 open source?

No. Fugu Ultra v2 is a closed model: its weights are not published, so you use it through Sakana AI’s own apps and API, or through cloud providers.

Who makes Fugu Ultra v2?

Fugu Ultra v2 is made by Sakana AI. It became available through the API on September 11, 2026.

Can Fugu Ultra v2 read images?

Yes. Besides text, it accepts images and files such as PDFs as input.

What are the alternatives to Fugu Ultra v2?

Models with a similar price from other companies include MiMo-V2.6-Pro-UltraSpeed, Qwen3.8 Max Prime and Claude Opus 5.5. You can compare them side by side on this page.