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Show HN: Mulligan Labs – multiplayer Magic: The Gathering in the browser

https://mulligan-labs.com/

Mulligan Labs is a browser-based playtester for Magic: The Gathering. No account or install needed. Just create a room, share the link, import a decklist from Archidekt or Moxfield, and play with mouse and keyboard (mobile support is not great right now).

Stack: SvelteKit on Cloudflare Workers, PartyKit (Durable Objects) for the authoritative game server. Clients propose actions over WebSocket; the server validates and broadcasts state.

My background is networking and my cofounder's is industrial design. Neither of us had shipped a codebase like this before. We built it over the last 5 months with heavy Claude assistance. Happy to get into what that actually looked like in the comments.

It's rough in places (the deck builder is just ok right now) but the core multiplayer loop is solid and we have played a ton of games on it with our Commander pod. We'd love feedback, especially from anyone who's played Cockatrice/XMage/Untap and has opinions on what a browser-native version should feel like.

( 4 comments | 3 points | on HN )
Re:Show HN: Mulligan Labs – multiplayer Magic: The Gathering... by nigardev on Thursday April 16, 2026 @02:19PM (#47797383)
how do you handle the authoritative state when a player disconnects mid-game. do you pause, let them reconnect, or just continue with the remaining players
Re:Show HN: Mulligan Labs – multiplayer Magic: The Gathering... by vrennat on Thursday April 16, 2026 @02:27PM (#47797490)
The game continues, we don't pause. There's a 5 second grace period to absorb refreshes, after which the server auto-passes priority on the disconnected player's behalf. They can reconnect anytime and the authoritative durable object places them back into current state.

This also only mostly matters in the "full priority" mode where players are actively passing priority all the time. In the more casual modes it doesn't come up too much.

Re:Show HN: Mulligan Labs – multiplayer Magic: The Gathering... by gorby2 on Thursday April 16, 2026 @01:07PM (#47796383)
dope! checking it out now
Re:Show HN: Mulligan Labs – multiplayer Magic: The Gathering... by vrennat on Thursday April 16, 2026 @01:08PM (#47796420)
Thanks, let me know what you think!