How to play-test a Magic deck online

Three kinds of play-test, and what each one tells you

The deck-site playtesters are good at the first row. Moxfield's Playtest button and Archidekt's playtester both deal hands from the list you are editing, and Archidekt's logs your mana and power as you go; Playgroup.gg will goldfish a pasted Moxfield or Archidekt link in the browser. If all you want is twenty opening hands, any of them will do. What none of them has is the second and third rows: a way to play one of your lists against another, and a way to carry the list to an opponent without exporting it again. That is where a shared table earns its place.

Goldfish on Untap.in: the list, then a Solo game

1. Bring the list in once. Decks, Import, paste the URL from aetherhub.com, archidekt.com, cardkingdom.com or any of 32 deck sites, or paste the list itself. It becomes a deck on your account with every printing you chose.
2. Open a Solo game from New Game. One seat, nobody waiting, the deck loads and you draw seven.
3. Play it out. Mulligan with a click, lay the land, cast the spell. Every card in your hand carries its cost and a Pay button that taps the lands for it, so the bookkeeping is one click and you are watching the curve, not counting pips.
4. Keep count of what matters. How often you keep seven. Whether there is a play on turn two. Which turn the deck's plan actually starts. Twenty hands is enough to see a pattern; the log keeps every one.

Try the other line

This is the thing a playtester cannot do and a paper goldfish cannot do either. You cast the three-drop on turn three, it was wrong, and you want to see the turn with the two one-drops instead. On Untap.in you press the curved arrow on the game bar, or Ctrl+Z, pick the point before the play, and the whole table goes back to it — hand, library, battlefield, counters. Then you play the other line from the same seven. Over a session that turns twenty opening hands into forty decisions, which is the number that actually teaches you the deck.

It works the same way at a real table: a misclick, a card dropped in the wrong zone or an attack nobody meant is a Rewind away, for every seat at once.

Prove the change: list A against list B

Most deck tuning is a feeling. You cut two cards, add two, and the deck seems better, and nobody ever checks. A Deck vs Deck game on Untap.in seats several of your own decks at one table — the old list in one seat, the new list in the next — and you play them against each other, moving round the table as each seat's turn comes. It is slower than goldfishing and faster than finding an opponent, and it is the only way to put the two versions of a deck in the same game. Deck vs Deck is part of Power Up, the subscription that funds the servers; a Solo game is not.

Then take it to somebody who wants to win

No amount of goldfishing tells you how a list does against counterspells, a board wipe or a deck that is simply faster. For that you need a person. The same deck you have been goldfishing is already on your account, so New Game, pick Magic, choose two seats or 3+, set the play style — Relaxed, Competitive, beginners welcome — and either send the link to a friend or let the public lobby fill the seat. Voice is built into the table, a friend can spectate and coach, and the game is recorded, so the one you lost is there to watch back.

2,733,779 Magic decks have been built on the site and 53,989 games were played in the last thirty days, which is to say there is normally somebody to play.

What a play-test on a shared table will not tell you

Untap.in does not enforce the rules. If you resolve a trigger in the wrong order or cast a sorcery at the wrong time, nothing stops you, the same as at a kitchen table. For most play-testing that is the point: there is no list of unimplemented cards, a card works the day it is spoiled, and a game sets up in the time it takes to paste a URL. If what you want to test is whether a specific interaction works the way you think, use a rules engine for that question — XMage is free and enforces everything, and Forge will goldfish against an AI with the rules on. Then come back to the table for the rest.