ℹ About OpenFile
A free, browser-based chess toolkit that replaces a shelf of separate apps — analysis board, opening trainer, tournament pairing software, rating calculators — with one tool that runs entirely on your own device.
What this is
OpenFile is a hub of nine small, focused chess tools covering the full arc of competitive improvement: understanding your own games, training against an engine, preparing an opening repertoire and checking it against your real games, running a tournament, and tracking a rating. Each is its own page, reachable from the home hub — a player, a coach, and a tournament director each land on the page built for them, rather than one sprawling app to learn.
Everything — including a full chess engine — runs in the browser. Game analysis uses Stockfish 18 (lite) compiled to WebAssembly and executed on your own machine; your PGNs and reports are never uploaded anywhere. Live games stream directly from the public lichess API straight to your browser, with no OpenFile server in that path. Reports save and load as plain files on your own machine — nothing is ever uploaded to any server.
The nine tools
For the player
| Tool | What it's for |
|---|---|
| Performance Analysis | A full diagnostic report from your chess.com / lichess games — opening strengths and weaknesses, phase-by-phase accuracy, tactical misses, time-trouble patterns, head-to-head records, and a prioritized training plan. Reports save as portable files that grow over time, and export to PDF. |
| Strength Report | A leaner, single-purpose sibling of Performance Analysis — upload or fetch a whole game set (combined across platforms, or one at a time) and get straight to opening/middlegame/endgame strengths-and-weaknesses and tactical-motif misses, with no training plan, puzzle trainer, or head-to-head section. |
| Game Analysis | One board, four modes: analyze any position, play a full game against the engine, follow a live lichess game move-by-move with feedback on every move played, or drill tablebase endgames against the clock. Endgames with few pieces left get an instant tablebase-perfect verdict alongside Stockfish's own evaluation. |
| Opening Explorer | Turns game history — yours, or an upcoming opponent's — into a browsable opening tree with win rates at every branch, then drills your repertoire with spaced repetition so weak lines surface more often until they stick. |
For the coach & tournament director
| Tool | What it's for |
|---|---|
| Swiss Pairings | Runs a full Swiss tournament from a roster — automatic pairings, bye handling, sibling/family conflict avoidance, live standings with official tiebreaks, wall charts, and a full explanation behind every pairing decision. |
| NWChess Pairings | Same tournament tools as Swiss Pairings, but built for importing an NWChess RosterTable.csv export directly — with a choice between best-effort Swiss pairing and strict FIDE (Dutch system) rules. |
| Compare Reports | Puts two saved reports side by side — one player's progress over time, or a head-to-head scouting comparison — with every metric delta highlighted. |
Rating utilities
| Tool | What it's for |
|---|---|
| USCF Rating Estimator | Predicts a post-event US Chess rating using the official published formula, ahead of the federation's own results. |
| FIDE Rating Estimator | The same estimate for FIDE Standard ratings, using FIDE's own K-factor rules. |
How it's built
- Private by construction. Game data and the chess engine both run on-device — none of it is ever uploaded to a server. The one exception is this page itself: loading it logs a page view and your approximate (city-level) location for the visitor map below, nothing more precise, and it's never tied to anything else you do on the site.
- Zero marginal infrastructure. Ships as a static site — no server, database, or hosting bill is required for any core tool. The visitor counter above is the one add-on that isn't, running on a small separate Cloudflare Worker.
- Installs like a native app. A Progressive Web App — add it to a home screen, and keep analyzing games with no connection at all once the engine has loaded, useful in a tournament hall with bad wifi. Live game streaming and account lookups still need a connection, since those come from lichess's/chess.com's public APIs.
- No account, no paywall. Every tool is free and open the moment the page loads — nothing to sign up for before getting value.
Development note
The current feature set — tablebase lookups, PDF export, opponent scouting reports, the coach dashboard, and the spaced-repetition opening trainer — shipped in a single focused push. A photo-based tournament-results reader was also built and tested, then removed after real-world photos (handwritten sheets, dense multi-column wall charts) proved unreliable to parse — a deliberate call to cut a feature that didn't clear the bar rather than ship something flaky.
🌍 Site visitors
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