Chrome Extension · Free to start

Train your opening lines — right in your browser

Chess Lines is a popup extension that drills your opening repertoire with spaced repetition. 86 lines, 23 openings, zero internet required after install.

Add to Chrome — Free See how it works
Works offlineNo account neededFree tier includedOne-time $10 unlock

How it works

Your repertoire, drilled to memory

Select an opening, make your moves when it's your turn, and the engine handles the opponent automatically. Get graded after each line and let spaced repetition resurface the ones you need most.

  • Practice view — interactive board with move validation and hints
  • Library view — browse all 86 lines with mastery progress badges
  • Spaced repetition — SM-2 algorithm resurfaces due lines automatically
  • Confetti celebration — every completed line fires a burst of color
Chess Lines extension showing the Caro-Kann Classical position

Features

Everything you need,
nothing you don't

Built for players who want focused repetition, not another chess platform to log into.

86 Opening Lines

23 openings covering the Italian Game, Sicilian, French, Caro-Kann, Queen's Gambit, King's Indian, and more — for both White and Black.

Spaced Repetition

The SM-2 algorithm tracks your mastery and surfaces lines exactly when you're about to forget them. Grade each line — Again, Hard, Good, or Easy.

Fully Offline

No servers. No syncing. No internet dependency after install. All data lives in your browser's local storage — completely private.

Popup Native

Lives entirely inside the browser toolbar popup — no new tabs opened, no side panels, no permissions beyond local storage. Click the icon, drill a line, close.

Move Validation

Powered by chess.js — every move is legally validated. Wrong moves are caught instantly, with an option to retry or get a hint.

Mastery Tracking

Each line tracks a mastery percentage that grows across multiple clean runs. One perfect run won't max it — real retention takes repetition.

Openings Library

23 openings. 86 lines.

6 lines are always free. Unlock all 86 with a one-time $10 upgrade.

Italian GameFree4 lines
Caro-KannFree4 lines
Ruy López4 lines
Sicilian Defense5 lines
Queen's Gambit4 lines
French Defense4 lines
London System3 lines
King's Indian Defense4 lines
King's Indian Attack3 lines
Nimzo-Indian3 lines
Catalan Opening3 lines
Grünfeld Defense3 lines
English Opening4 lines
Dutch Defense3 lines
Réti Opening3 lines
Pirc Defense3 lines
Colle System3 lines
Modern Defense3 lines
Vienna Game3 lines
Budapest Gambit2 lines
Scotch Game2 lines
Alekhine Defense2 lines
Four Knights2 lines

Pricing

Start free. Unlock everything for $10.

No subscription. No account. Just a one-time payment for lifetime access.

Free
$0

Get started immediately — no payment required. Practice the foundational Italian Game and Caro-Kann lines forever.

  • 6 opening lines (always free)
  • Full spaced repetition engine
  • Mastery tracking
  • Works offline
  • 80 premium lines locked
Add to Chrome — Free
Best value
Lifetime
$10one-time

Unlock the full library forever. No recurring fees, no account required — enter your license key directly in the extension.

  • All 86 opening lines
  • 23 complete openings
  • Full spaced repetition + mastery
  • Lifetime access — no renewals
  • Works completely offline
Add to Chrome — $10 Lifetime

Ready to own your openings?

Add Chess Lines to Chrome for free and start drilling the Italian Game and Caro-Kann today. Upgrade to unlock all 86 lines whenever you're ready.

Add to Chrome — Free See pricing