Test the deck before the table does.
Paste any decklist and the Lab plays 10,000 opening hands, then tells you in one sentence how often you keep, flood, or run short on lands. Swap a card and see what changes.
Try it on any tournament deck first. No account needed.
The Report Card loop
Your list, exactly as you built it
Shuffle, deal seven, mulligan down to the floor
The deck grades itself
Every run deals this many hands, and the right column is what it tells you, in the Lab's own words.
A microscope for a deck you have not sleeved yet
The goldfish table, with a coach
Draw a real hand and the Mulligan Coach calls Keep, Risky, or Mulligan, with its reasons. Cards you can't cast yet glow and name the color you're short.
- Replay any hand from its seed, or one a friend sent you
- Rewind a draw and take the other line
Mulligan Coach
The Coach reads a real hand, shows all three factors it weighed, and leaves the decision to you.
The deck grades itself
The Lab plays 10,000 hands and writes the verdict as a sentence: how often you keep, flood, and hit your early land drops. The Mana Doctor checks your sources against your pips turn by turn, taplands included.
- When the deck is shaky, it says which part: the hands, the colors, or the curve
Mana Doctor · one color
It tells you whether you will have drawn a source of each color by a given turn. It does not account for mana already on the battlefield.
Swap one card. Watch what moves.
Cut a land for a mana rock and both versions replay the same 10,000 hands, so any difference comes from the card you swapped. Apply it, or leave it as a what-if.
- Ask, and it picks the cut for you and says why
- Suggestions come from your own shelf and the combos you're one card from
The Bench · one for one
out
a card you cut
in
a card you bench
Re-measured on both sides
Both sides re-run the same hands off one fixed seed, so any difference comes from the swap and not the shuffle.
Four ways to look at the same list
Edit it as text, or read it as stacks, a grid, or a compact list. Group and sort it any way you like, or show only what you don't own.
- Import a pasted list, a Moxfield URL, or an Archidekt link
- Your own copies come first when you pick a printing
- Partner pairs seat together, with the shared color identity applied
Four views, one list
The options on the arrange toolbar. Text is the editable one, and any arrangement you like can be shared as a link.
Build the illegal thing
The builder never stops you. Put an off-color card in a Commander deck, run five copies in Modern, seat a partner pair the rules do not allow. The deck saves.
The Legality Report checks the deck every time you open it: bans, copy limits, color identity, the commander, and partner pairs. Four of one printing and four of another count as eight.
It also says how much it checked. Commander and the constructed formats get every card checked. Brawl and Oathbreaker get size and singleton only, and the badge says so, so a deck that was only counted never reads as clean.
The combos you hold, and the ones one card away
See the Commander Spellbook combos your deck already holds, and the ones a single card away in your colors. It reads a combo list; it does not read card text and infer a loop, so it will only ever show you combos somebody has written down.
- Each missing card shows up once, so one missing staple can't crowd out the rest
Combo Radar · two tiers
Your list is checked against Commander Spellbook's combo list, so every combo here is one somebody has written down.
What the deck is actually made of
See the deck by what it's built around, then drill down to the cards doing each job, biggest groups first.
- Fix the mana with cards already on your shelf, untapped lands first
- Share a link with the archetype, the stats, and a Get these cards button that lists only what a friend is missing
Synergy lens · four levels down
- lenswhat the deck is built around
- faceta group of related jobs
- tagone job a card does
- cardsthe cards carrying it
Start from one of five angles (strategy, function, resource, role, or audience) and drill down to single cards, biggest groups first.
Every deck you build and every deck you share is free.
Your deck's archetype, named as you build
Each list is matched to an archetype by the jobs its cards do, its curve, and its colors, and you see how much of the deck backs the name. When nothing fits well, it stays unnamed.
- Renamed after every card you add or cut
One decklist, read as concepts
- Removalcounted
- Rampcounted
- Card drawcounted
- Board wipescounted
Every theme it counts has its own page, open to anyone.
The metagame, filtered your way
Tournament decklists from TopDeck.gg events land daily. Filter by format, commander, and dates, and sort by finish or win rate. If you play cEDH, this is the deepest data on the site. If you play Standard, be warned: the events we ingest barely cover it.
- Open the Lab on any of them, no account needed
- The cEDH leaderboard needs a minimum number of games, so one lucky win can't top it
- Copying a tournament list into a deck of your own is not built yet
cEDH metagame · top archetypes
- Simic Tempo3.6%
- Esper Tempo1.7%
- Witch-Maw Tempo1.3%
- Jeskai Tempo1.1%
Live from tournament results over the last 30 days. The classifier placed 18% of 6,313 decks, and shares divide by every deck in the window, so they sum to that coverage. As of 2026-10-16.
The bridge a spreadsheet never had
Take a list apart
Bring a deck in from Moxfield, Archidekt, or a paste, and put it under the Lab. Or read what the format is actually doing first.