Jan

Open source ChatGPT alternative that works 100% offline.

Jan is an open-source ChatGPT-shaped desktop app that runs 100% offline. The local server is localhost:1337/v1, OpenAI-compatible, so editors can talk to it the same way they talk to LM Studio.

Download, pick a model, chat. No account. The point is the UI, not a new engine — under the hood it is still local weights on your machine.

Max context: Whatever your RAM allows
Free tier: Unlimited and private
Requirement: Nothing — no account

Endpoint

Base URLhttp://localhost:1337/v1

Rate limitNone — it is your machine

OpenAI-compatible
text

Code examples

npm install openai

import OpenAI from 'openai'

const client = new OpenAI({
  baseURL: 'http://localhost:1337/v1',
  apiKey: 'not-needed'
})

const response = await client.chat.completions.create({
  model: 'llama3.3-70b',
  messages: [{ role: 'user', content: 'Explain closures in one paragraph.' }]
})

console.log(response.choices[0].message.content)

pip install openai

from openai import OpenAI

client = OpenAI(
    base_url="http://localhost:1337/v1",
    api_key="not-needed",
)

response = client.chat.completions.create(
    model="llama3.3-70b",
    messages=[{"role": "user", "content": "Explain closures in one paragraph."}],
)

print(response.choices[0].message.content)

curl http://localhost:1337/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "llama3.3-70b",
    "messages": [{"role": "user", "content": "Explain closures in one paragraph."}]
  }'

Models you get for free2

Llama 3.3 70Bllama-3.3-70b
Qwen 3qwen3