Coinkeep

Earn it. Bank it. Defend it.

Most economy mods give you a number in a chat command. Coinkeep gives you work that pays, a market that reacts to what you sell, cash you can hold in your hand, and a vault someone can crack open — a full loop, not a balance field.

Quests — always something paying

180 quests across 10 chapters: Mining, Combat, Tools & Armor, Building, Farming, plus one chapter per vanilla advancement tab.

• Nothing to accept and no NPC to find. Play, and progress tracks itself.
• Gathering quests repeat forever on escalating tiers. Progress is a lifetime total that is never reset — mine 40 iron and all 40 count toward the next threshold.
• Almost nothing is gated. Only 10 dependencies exist in the entire book, and each is a real requirement.
• Two ladders show progression: within a quest's tiers, and across its whole chapter.

The Market — supply and demand

• Buy from a categorised catalog, including Rare finds (Elytra, Totem, Nether Star) and Signature gear — named, pre-enchanted endgame pieces like The Prospector.
• Sell your haul. Each sale saturates that item's demand, so it pays a little less than the last, and demand recovers over time. Grinding one block forever stops being worth it, without anything ever being locked.
• Demand is per player, so nobody can crash the market for everyone else.

Cash you can actually carry

Eighteen denominations, $1 to $100,000,000. Real items you can stack in a chest, hand to another player, or lose in lava. Your banked balance survives death — the cash in your pockets does not.

Vaults & robbery

• Money in a vault is never lost on death.
• Only the owner can open it — and only the owner can break it. A thief can never destroy someone's savings.
• Break your own and you get the whole vault back as an item, money still inside. Place it anywhere and it is all still there.
• Carrying a loaded vault is the risk. It is an ordinary item, so dying drops it — and whoever loots it gets a locked vault they will have to crack.
• A Vault Cracker is the only way to rob one. You cannot see how much is inside before you commit. Cracking clears the claim, so the emptied vault is then free to take.

Change the shop from chat

Don't like a price? Change it. Operators can edit the catalog from in game — no datapack to write, nothing to restart:

• /coinkeep shop add <price> lists the item you are holding, keeping its stack size, custom name and enchantments — so a named, enchanted sword sells as that exact sword.
• /coinkeep shop price, sellprice, count, limit and category adjust anything already in the catalog.
• /coinkeep shop remove takes an item out; restore and restoreall put things back exactly as they shipped.
• Ids tab-complete, and /coinkeep shop list shows every tab and id.

Changes apply instantly, for everyone — no reload, no restart. Your edits are saved as ordinary JSON in your world folder, laid out as a datapack, so you can copy them into another world, send them to someone, or open and hand-edit them. Nothing is ever destroyed: removing an item hides it, which is why restore always works.

One rule is enforced. Nothing may sell for at least what it costs to buy, because that would let anyone buy an item and sell it straight back forever. Edits that would do it are refused with an explanation.

Built for modpacks — and for your own world

Every quest, chapter, shop category and shop entry is a JSON file in a datapack registry. Add, retune or override anything without touching the jar. Items from any other mod work by id, and content is validated on load so a typo cannot silently strand a quest.

Datapack edits are picked up when a world loads. (Minecraft builds datapack registries once, as the world opens, so /reload rebuilds recipes and loot but cannot rebuild these — the in-game commands above are the instant route.)

Companion mods get their own Shop tab rather than being dumped into Materials: drop a shop_category JSON with an id, a name and a sort order, point your entries at it, and the tab appears exactly when your mod is installed and disappears with it. Highroller (our casino mod) is the worked example — its 90 machines, tables and decor blocks all sell from a Highroller tab of their own.

Commands

/balance	check your balance
/buy · /sell	trade without the GUI
/pay	send money to another player
/withdraw · /depositall	convert balance to and from banknotes
/addbalance	operator payouts
/coinkeep shop	operator; add, remove and reprice the catalog
keys	J Ledger · K straight to the Shop (both rebindable)

Versions

Available for Minecraft 1.21.1, 1.21.11 and 26.2 — NeoForge on all three, same features everywhere (the 26.2 build runs on Java 25, as all of Minecraft 26.x does). Balances, quest progress and market demand are stored per player as data attachments, with no custom packets anywhere.