Free online chess analysis with AI commentary
Upload a PGN or play in your browser — Kingside runs Stockfish 18 on every move and explains what happened in plain English, not just numbers.
Unlike most online analyzers, you don't get only +1.5 or a yellow “inaccuracy” tag. You get a text explanation: “The knight on f3 doesn't reach the b7 attack in time; after Nf6 Black takes the initiative.” Works on any phase — opening, middlegame, endgame.
What the Kingside analyzer does
Stockfish 18 in your browser. The engine runs locally via WebAssembly. No queues, no depth limits — your machine evaluates as long as you want. No server connection needed; your game never leaves the browser.
AI commentary on every move. A language model looks at the Stockfish evaluation, principal variations, and position type, then explains in English or Russian why a move was strong, where the mistake is, and what the position threatens.
Maia-3: the human-move model. Alongside Stockfish, we run Maia-3 — a Microsoft Research network trained on real human games at different rating levels. It shows what a human at your rating would play, not just the engine's top move. Useful for preparing against specific opponents.
External Engine bridge. Plug your own Stockfish from your PC. Depth 35+, no limits, latest NNUE networks. See external engine docs.
How to analyze a game
- Play on Kingside — analysis opens automatically after the game.
- Import a PGN — paste any PGN from chess.com, lichess, ChessBase, or a file.
- Drop a board screenshot — Kingside detects the position from a photo or screenshot and opens it in the analyzer.
Loading takes a second, analysis 5–30 seconds depending on length. Output: variation tree, per-move evaluations, AI commentary, highlighted mistakes and critical moments.
How it compares
| Feature | Kingside | Chess.com Analysis | Lichess Analysis |
|---|---|---|---|
| Free Stockfish | Stockfish 18 WASM | depth caps, premium for full | yes |
| Text explanation per move | AI commentary | in paid Coach | numbers only |
| External engine bridge | yes | no | no |
| Maia (human-move model) | Maia-3 | no | separate project maiachess.com |
| Import PGN, lichess study, chess.com URL | yes | yes | yes |
| No subscription | fully free | no | yes |
FAQ
- Is my game private?
- Yes. Stockfish 18 runs in your browser locally; we only send the game to our server to generate AI commentary, and we don't store it after. With External Engine on, the game never leaves your machine.
- Can I analyze lichess or chess.com games?
- Yes. Both export PGN — copy the text and paste it into Kingside.
- What depth do you reach?
- Stockfish WASM — depth 20–25 by default, you can raise it. External Engine — no cap (35+ in practice).
- How much does it cost?
- Free. No subscription, no ads, no per-game limits. Details on open assets.
- Mobile?
- Yes, any modern mobile browser. Stockfish WASM runs on iOS and Android. Long games take longer than on desktop.
Open the Kingside analyzer and review your last game — free, no signup.