Kilo Code is a 100% free, open-source AI agent extension for VS Code and JetBrains with over 340,000 installs. While most AI coding agents require paid subscriptions, we've partnered with OpenRouter to bring you access to a powerful frontier model for free. And by free we mean really free: No rate limits and fast code generation.
The Model: Horizon Beta
Horizon Beta is a stealth, frontier AI model that many in the developer community speculate originates from OpenAI (some people even call it GPT-5).
This model can be better than Sonnet or Opus 4, especially in tasks like generating good-looking UIs.
What is a "stealth" model? It's a fancy term for: "We won't tell you who is behind this model and make it 100% free, in return we're getting usage stats". The last "stealth" model announced by OpenRouter was by OpenAI.
How to use Horizon Beta in Kilo Code
Follow 3 simple steps:
Install our VS Code extension
Install our VS Code extension if you haven't already (we're at 180,000+ installs!) and sign up.
Change your default model to Horizon Beta
Go to Settings in the extension and select Horizon Beta as your default model.
You're done. Start typing!
Begin using Horizon Beta for all your coding tasks with no rate limits.
Why Choose Horizon Beta?
100% Free
No subscription fees, no rate limits, no hidden costs. Use a frontier-level AI model completely free.
Frontier Performance
Potentially better than Claude Sonnet or Opus 4, especially for UI generation and complex coding tasks.
Fast Generation
Quick response times for efficient coding workflows without the wait.
Excellent for UIs
Particularly strong at generating beautiful, functional user interfaces and frontend code.
Community Speculation
Some people suspect this is another stealth model from OpenAI. The developer community has been buzzing with theories that Horizon Beta might be an early version of GPT-5 or another advanced OpenAI model being tested in the wild.
While we can't confirm the model's origins, what we can confirm is its impressive performance and the fact that it's completely free to use through Kilo Code.
Ready to try Horizon Beta?
Join over 180,000 developers using Kilo Code and start coding with a frontier AI model for free.
Questions? Join our Discord community or contact support