Fugu Ultra
About this model
Fugu Ultra is an AI model from Sakana AI, made available through the API on June 24, 2026. It can read up to 1,000,000 tokens in one request, roughly 1,875 pages of text, and write up to 128,000 tokens in a single answer. Besides text, it accepts images as input.
Through the API it costs $5 per million input tokens and $30 per million output tokens. It is among the more expensive models we track, a price usually reserved for the most capable, flagship-class models.
It supports extended reasoning: it can "think" step by step before answering, which helps on maths, code and complex questions. It can call tools and functions, so developers can connect it to search, databases or other software.
Quality scores
Rankings →Not rated yet. Independent test results usually appear a few weeks after a model is released.
Where to use it
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.
Use it in your code
Call Fugu Ultra 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", "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",
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",
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.
What it costs in practice
- 1,000 chat replies$11.50
- Summarise a 100-page document$0.28
- An app with 10,000 requests a day for a month$5,100
Similar-priced alternatives
| Model | Inputi | Outputi | Contexti | |
|---|---|---|---|---|
Claude Opus 5Anthropic | $5 | $25 | 1M | Compare with ⇄ |
MiMo-V2.6-Pro-UltraSpeedXiaomi | $4.35 | $8.70 | 1M | Compare with ⇄ |
Qwen3.8 Max PrimeAlibaba Qwen | $4 | $12 | 1M | Compare with ⇄ |
GPT-5.6 Sol ProOpenAI | $4 | $20 | 1.1M | Compare with ⇄ |
Ember-1Fireworks AI | $3 | $15 | 1M | Compare with ⇄ |
Aion 3.5Aion Labs | $3 | $6 | 256K | Compare with ⇄ |
Frequently asked questions
- How much does Fugu Ultra cost?
- Fugu Ultra 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?
- Fugu Ultra 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 open source?
- No. Fugu Ultra 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?
- Fugu Ultra is made by Sakana AI. It became available through the API on June 24, 2026.
- Can Fugu Ultra read images?
- Yes. Besides text, it accepts images as input.
- What are the alternatives to Fugu Ultra?
- Models with a similar price from other companies include Claude Opus 5, MiMo-V2.6-Pro-UltraSpeed and Qwen3.8 Max Prime. You can compare them side by side on this page.