Frequently Asked Questions

BuildMyDeck is a deck-building assistant for Magic: The Gathering Commander format. You upload your card collection as a CSV, choose a commander, and the engine builds a legal, synergy-optimized 100-card deck from the cards you already own.

Any CSV with a "Name" or "Card Name" column works. Exports from Moxfield, Archidekt, Deckbox, and TCGPlayer collection manager all import cleanly. The file must be under 10 MB.

By default the engine builds using only cards in your inventory. You can switch to "Best possible" mode to see the optimal deck regardless of ownership — the difference becomes your upgrade path and acquisition list.

Inventory-based builds typically finish in 30–90 seconds. Full card pool (oracle) builds take 3–5 minutes when the nightly cache is warm. The cache refreshes automatically at 3 AM ET — if you build right after it starts, the first run may take 30–60 minutes. You'll see a live progress log while it runs.

Cards are scored against the commander's strategy profile — synergy tags, package targets, bucket weights, and mana curve requirements. The engine runs inventory-blind scoring first (so the "best possible" deck is always visible), then filters to owned cards. Combo lines from Commander Spellbook are detected and woven in when they fit the strategy.

Five bracket levels: Casual (1), Precon-appropriate (2), Powered (3), Competitive (4), and cEDH (5). Each bracket changes slot weights, land counts, interaction density, and game-changer policies to match the Commander Spellbook bracket guidelines.

Use the Refine controls to push the build in a different direction (more interaction, less combo, stricter owned-only, etc.) and rebuild. The "Build Notes" panel on any result also explains which package and score drove each slot decision.

Combos are woven in when the strategy supports them and you own the pieces, but they're never forced. Combo posture (none / light / heavy / required) controls how aggressively the engine pursues them. At "light" (default) a combo is included only if it fits the natural slot budget.

3 free builds per day, resetting at midnight. These don't roll over. New accounts also receive 5 bonus credits on sign-up. Purchased credits are used after your daily quota and never expire.

Starting a new deck build or an upgrade run consumes one credit. Viewing results, exporting to CSV, the optimization panel, and the explainability panel are all free.

Yes — unused purchased credits are refundable within 30 days. Email support@buildmydeck.app with your username and approximate purchase date.

Yes — your inventory CSV is stored in an isolated per-user folder to power repeated builds without re-uploading. You can replace it any time from the dashboard. See our Privacy Policy for full details.

Submit a request on our Data Deletion page. We'll confirm within 5 business days and complete deletion within 30 days.