WHY WE
BUILT THIS

The short version: a drawer full of scoresheets I never looked at again.

ChessDiary started as a problem I had, not a business plan. I'm a student and a club-level tournament player, and for years my chess record lived in three places that never talked to each other.

Every over-the-board game I played left a paper scoresheet behind. I'd fold it up, drop it in my bag after the round, and — almost without fail — never open it again. By the end of a season I had a shoebox of handwritten notation I couldn't be bothered to transcribe, covering losses I knew I should study but never did. Meanwhile my online games were somewhere else entirely: blitz and rapid on Chess.com, correspondence games on Lichess, each platform holding its own slice of my history with no way to see all of it side by side.

The actual losing pattern was hiding in plain sight across all three of those places at once, and I had no way to see it. I'd blunder the same type of tactic in a paper tournament game in March and again in a Lichess game in June, and never connect the two, because nothing put them in front of me together.

So I built that. ChessDiary reads a photo of a handwritten scoresheet with Gemini AI and turns it into a clean move list. It pulls your existing history straight from the Chess.com and Lichess public APIs with one-time account linking, no manual PGN exports. And every game, regardless of where it came from, gets run through Stockfish — the same engine used at the top level of the game — so the blunders, mistakes, and inaccuracies are flagged with real centipawn numbers, not a guess.

WHAT CHESSDIARY IS NOT TRYING TO BE

It's not trying to replace Chess.com or Lichess as a place to actually play. It's not a coaching platform with a human on the other end. It's the layer underneath all of that — the diary part — that collects everything you've already played and makes the patterns visible, whether the game happened on a board with a pencil or on a phone screen at midnight.

WHERE IT STANDS TODAY

ChessDiary is free to use on Web and in closed beta on Android, built from a single codebase for both. It's ad-supported rather than subscription-based, which is also why you'll see a privacy policy that's honest about Google AdSense and AdMob rather than pretending they're not there. If you've read this far, you probably have the same shoebox-of-scoresheets problem I did — the guides are a good place to start, or jump straight into a real example analysis report to see what the engine actually flags in a full game.

THE AUTHOR