MTG deck testing tool for opening hands, early turns, and deck comparison.

Paste a decklist. Draw hands. Goldfish turns 1–5. Compare two decks side by side. Works on mobile.

→ Try it at keep7.vercel.app

Keep7 helps you answer real play questions before you sit down at a table:

• Is this opener keepable? Draw 7-card hands, keep or mulligan, see your next 3 draws.
• How does my curve play out? Goldfish turns 1–5 — tap lands, cast spells, see available mana.
• Which version of this deck starts better? Run 20 opener trials for each list, get a plain verdict.

• Parse any standard decklist format
• Draw a 7-card opener, keep or mulligan
• Reveal next 3 draws after you keep
• Track session stats: keep rate, land distribution, flood/screw risk

• Simulate turns 1–5 against an empty board
• Play lands from hand, tap for mana, cast spells
• Action log tracks what happened each turn

• Compare two decklists across 20 simulated openers each
• Stats: keep rate, avg lands, T3 land %, flood/screw risk
• Plain-English verdict you can act on

• Next.js 15 (App Router) + React 19
• TypeScript throughout
• CSS Modules — no CSS-in-JS, no utility framework
• Scryfall API — card data and images, with retry/fallback
• MTGJSON — random web deck loading
• Fully client-side — no custom backend, no auth, no database

git clone https://github.com/fuzmaster/keep7.git
cd keep7
npm install
npm run dev

Open http://localhost:3000.

One card per line:

4 Lightning Bolt
4 Goblin Guide
20 Mountain

Handles Moxfield export format automatically (set codes, collector numbers, etc.).

• Paste a decklist — plain text, one card per line
• Moxfield / Archidekt URLs — import via the URL field
• Random web deck — loads from MTGJSON by deck type

• Scryfall requests are batched, rate-limited, and retried on failure
• If Scryfall is unavailable, the app falls back to placeholder cards — simulation still works
• Card data is cached in localStorage by deck hash (7-day TTL, up to 5 decks)
• localStorage failures are handled gracefully

src/
 app/ Next.js App Router pages and layout
 components/ UI components with colocated CSS modules
 hooks/ State logic for each mode (useHandTest, useGoldfish, useRace)
 lib/ Business logic: parser, engine, scryfall, storage, metrics
 types/ TypeScript interfaces

Keep7 runs entirely in your browser. Deck text and session data never leave your device. The only external requests are to Scryfall (card images/data) and MTGJSON (optional random deck loading).

MIT