The developer kit: saves, trophies and scores

The kit is one file you add to a browser game. It needs no keys and no server of your own. Everything is on the Developer kit tab of your game, with the file to download and an example.

What it does

• Saved progress: one value per player, up to 64 KB, that follows the player to any device they sign in on.
• Saves on several devices: every save has a revision number. Load with Kit.loadSave() and save with Kit.saveOver(data, revision): if the player saved on another device in between, nothing is overwritten and your game gets the newer save back, so it can ask the player which one to keep. The plain Kit.save() always replaces.
• Controllers: Kit.gamepad() reads the controller in the standard layout, after the layout the player set under Settings › Controller. A game that reads the controller directly still works; it just does not see the player's layout.
• Trophies: you define them on the tab; the game awards one by its key. The game's page shows them, and tells a player when they earn one.
• Score tables: each keeps every player's best score. The top ten are shown on the game's page.
• Players: your game learns whether the player is signed in, their display name, and an id for them that stays the same each time they return to your game. It can send a guest to sign in.
• Ads between levels: on a free game with ads switched on, your game can ask for an advertisement at a natural pause. At most one every two minutes, and the player can continue after five seconds.

How it stays safe

Your game never gets a player's account. It sends a request to the page it is shown on, and the site answers for the signed-in player and for your game only. A game learns whether the player is signed in, their display name, an id that works only in your game, and the names on your own score tables. Nothing else, and it cannot read or change another game's data.

Limits to know

• Saving, trophies and sending scores need a signed-in player. Reading a score table does not. Keep a fallback, such as the browser's own storage, for players who are not signed in.
• The kit works when the game is played on its page here. It does not work in games that open in their own tab, or in downloads.
• Downloads started from the desktop app get a folder for their saves in the LUDOMINT_SAVE_DIR environment variable. Write your save files there and they follow the player to their other computers, up to 100 MB. The app also passes LUDOMINT_LICENCE and LUDOMINT_PUBLIC_KEY, so a game can check for itself that the player owns it.
• Scores are sent by the game, which runs on the player's device, so a determined player can fake one. Set the lowest and highest score each table accepts, and remove any score that cannot be real, on the Developer kit tab.
• Up to 50 trophies and 10 score tables per game.