Kimi K3 Complete Guide: The Open-Source AI Model That Just Beat The Fable

How to use Moonshot’s new model for websites, large coding jobs, research, documents and long-running AI work

Kimi K3 Complete Guide: The Open-Source AI Model That Just Beat The Fable

TL;DR

  • Kimi K3 has entered the Arena Frontend Code leaderboard at number one, surpassing Claude Fable 5 and GPT-5.6 Sol.
  • This marks a significant upgrade for Moonshot, moving from number 18 to number one in a single release.
  • Kimi K3 ranked first in six out of seven frontend categories tested, only coming second in gaming.
  • The model features frontier-level coding capabilities, one million tokens of memory, vision, and tool use.
  • It employs a Mixture of Experts design with 2.8 trillion total parameters, activating a subset of experts for specific tasks.
  • Kimi K3 is specifically designed for demanding tasks like reading entire software projects, building websites from screenshots, and processing large document collections.
  • It includes Kimi Delta Attention and Attention Residuals to manage information across long files and complex reasoning.