Little Alchemy Co-op by Der_Floh

A browser extension (tested in Chrome and Firefox; other Chromium browsers such as Edge and Brave use the same build) that lets friends play Little Alchemy classic together:

• Shared discoveries: everything one player discovers appears in everyone's game within about a second: in the library, the element counter and the save.
• Shared canvas: everyone sees and plays on the same workspace. Elements, drags and combinations show up for all players, and you can see everyone's cursor.
• Catching up: when you come back to a room, a card shows what the others discovered while you were away.
• Host controls: the host can lock the room, remove a player, or hand the host role to someone else.

It runs on top of the official game. There is no server to run: players connect directly to each other (WebRTC, via PeerJS).

Unofficial fan project, not affiliated with or endorsed by the makers of Little Alchemy. It bundles none of the game's code or assets.

1. Install the extension (see below) and open <https://littlealchemy.com/>.
2. Click the Co-op button at the top left, then Create room.
3. Send your friend the 6-character code, or click Invite link and send that (https://littlealchemy.com/#coop=K7M4PX).
4. Your friend opens the link (or types the code under or join a friend).
5. Play. When someone discovers something new you get a pop-up, and the Activity list shows who made what.

On the shared canvas:

• Anyone can move or combine any element. While someone is dragging an element it's outlined in their colour with their name, and nobody else can grab it or drop onto it.
• Everyone sees the same arrangement, fitted to their own window: nothing ends up off-screen or behind the library, even on a smaller screen.
• The game's clear button removes only the elements you placed or made.
• Other players' cursors can be hidden under ⚙ → Show other players' cursors.

Good to know:

• Progress is merged both ways. When you join, everything you already had goes to the room and everything the room has comes to you, permanently. The first time you ever join a room, your save is backed up once; you can restore it under ⚙ → Restore backup (after leaving the room).
• A room lives as long as someone is in it. If the player who created the room leaves, someone else takes over automatically. If everyone leaves, nothing is lost (every save holds everything); the next person to join the same code opens it again.
• Joining replaces your canvas with the room's (your progress is untouched; elements can always be dragged from the library again).
• Reloading the page rejoins your room automatically. Leave room stops that.
• Use one Little Alchemy tab at a time; a second tab stays passive until you click Use co-op in this tab.
• Rooms hold up to 8 players.
• Everyone needs version 0.2 or later. Version 0.2 introduced a new connection protocol, so 0.1 can't share a room with newer versions; the game tells you if that happens. Versions from 0.2 on play together.

Host controls (in the Players list, for whoever is host):

• Lock room: nobody new can join; players who were already in can reconnect.
• Kick: removes a player; they can't rejoin until the room has emptied.
• Make host: hands the host role (and these controls) to another player.