I Tried Kimi K3 for a Week. Here’s What Happened.

A few days ago I posted my first impressions of Kimi K3 on LinkedIn. Since then, I’ve been using it daily for real work — not benchmarks, not demos. Here’s what actually held up.

The Context Window Isn’t Marketing

I tested the 1M token claim the hard way: dumped a 40,000-line codebase into it, then asked it to refactor a utility function that was referenced across 12 files. It traced every call site correctly. No “remind me what file X does” loops. That’s the difference between reading specs and actually using it.

Frontend Coding: The Hype Checks Out

Kimi K3 is #1 on Arena’s Frontend Coding leaderboard right now, ahead of Claude Fable 5. I was skeptical, so I gave it a real task: build a responsive dashboard with real-time charts, dark mode, and collapsible sidebar. The code was clean, state management made sense, and it handled edge cases I hadn’t explicitly asked for. Not perfect, but genuinely competitive.