Introducing Kojo, our latest model

Kojo scores 92.2% on SWE-bench Verified and 86% on Terminal-Bench 2.1. You can chat with it for free at kojo.sh, and its API at api.kojo.sh starts at $0.175 per million input tokens.

Empero26 October 20265 min read

Kojo is our latest model. Ahead of the launch we opened it up for free at kojo.empero.org, which is now kojo.sh. Since then it has handled billions of tokens a day at a very low serving cost. Within a few hours, about 500 accounts signed up just to farm free tokens. They cost us about $3.

Today Kojo gets its own home at kojo.sh, its API opens to everyone at api.kojo.sh, and there are plans for people who want more.

Two benchmarks

Full evaluation suites were prohibitively expensive for us, so we picked the two benchmarks with the best signal per dollar.

Benchmark	Kojo
SWE-bench Verified	92.2% (461 of 500)
Terminal-Bench 2.1	86%

How we use it

Internally we have been running Kojo alongside an Opus 5.5 advisor, and two things stood out. First, its performance relative to its price was better than we expected. Second, Opus 5.5 often did not appear in the logs at all: Kojo was handling the task from start to finish without consulting the advisor, and doing it well.

That is why we now use Kojo to build the infrastructure that serves our models, and why it has been involved in training others: mainly a text-to-speech model we hope to release soon, and an architecture for local use that should train on minimal compute.

What Kojo does in the chat

Searches the web and reads the pages it finds, so its answers use current information.
Reads the images you attach.
Builds things: web pages, small games, drawings and art, with a live preview in the chat.
Works the way you do: sign in with an Empero account to give it your own instructions and skills (SKILL.md files), and to have your chats on every device.
Shares chats: send a chat as a link, and anyone can continue it as their own.

Kojo is free at kojo.sh, without an account. Signing in keeps your chats on every device and gives you more room each day.

The API

Kojo speaks the OpenAI chat completions API, so existing SDKs and tools work once you change two settings, the base URL and the key:

from openai import OpenAI

client = OpenAI(base_url="https://api.kojo.sh/v1", api_key="sk-kojo-...")
reply = client.chat.completions.create(
    model="kojo",
    messages=[{"role": "user", "content": "Hello, Kojo."}],
)
print(reply.choices[0].message.content)

Streaming, tool calls and images work as they do with other OpenAI-compatible services. You create keys, follow your usage and read the documentation at platform.kojo.sh.

Pay as you go costs $0.175 per million input tokens, $1.00 per million output tokens and $0.02 per million cached input tokens. That is a launch price for two weeks from 26 October. After that it is $0.20, $1.25 and $0.02.

Plans

Choose a plan in Kojo under Settings, then Plan, or at platform.kojo.sh. You can pay by card or from your Empero balance.

Plan	Price	Usage	API keys
Free	$0	Chat with a daily allowance	None
Go	$1 a month	Starter usage	1
Basic	$5 a month	5× Go	2
Plus	$15 a month	About 20× Go	5
Pro	$35 a month	About 35× Go	5
Max	$50 a month	50× Go	10
Flex	Pay as you go	At the prices above	No limit

Moving from kojo.empero.org

kojo.empero.org now forwards to kojo.sh, and your chats and sign-in come with you. If you use the API, change the base URL to https://api.kojo.sh/v1. Your keys stay the same.