How running the engine in your browser changes what’s possible.
Most online chess analysis tools work the same way: you send your game to a server, a powerful machine on the other end runs the engine, and the result gets sent back to your browser. That server time costs the site money — real compute, every single request — which is exactly why free accounts on other platforms get capped at something like one full analysis a day.
See The Mate takes the other approach. Stockfish 18 is compiled to WebAssembly (WASM) — a format that lets code written in languages like C++ run at near-native speed directly inside a browser tab. The engine isn't running on a server somewhere; it's running on your own device, using your own device's processor, the moment you load the page.
No server means no per-analysis cost, which is the entire reason this can stay free with no daily cap. It also means no queue — you're not waiting behind other users' requests, because there's no shared server being divided among everyone at once. And it means your games never leave your device for analysis: the positions are evaluated locally, so nothing about the game itself needs to be uploaded anywhere.
The honest downside is that analysis speed depends on your own device instead of a dedicated server. A recent laptop or desktop handles Stockfish 18 comfortably. Older phones are slower simply because they have less raw processing power available — the engine still runs and still gives accurate results, it just takes longer to reach the same search depth. There's no separate app to install either way; it's the same WASM binary running inside the browser tab regardless of device.
A lot of "free" software online is free until it costs the provider money at scale, at which point limits show up. Client-side analysis sidesteps that problem structurally rather than through a policy decision — there's no compute bill tied to how many people use the site or how many games get analysed, so there's no future version of this where full analysis quietly moves behind a paywall because the server costs became unsustainable.
See it in action on Analyze, or read more about how to read what the engine tells you.