Viper Economy

Viper Economy is a server-side Fabric economy mod for Minecraft 1.21.x, 26.1.x, 26.2.x and 26.3.x. It adds virtual or physical currency, a server shop GUI, player chest shops, player-to-player payments and purchasable command rewards (claim blocks, ranks, kits). No client mod is needed: vanilla clients can join and use everything, and the mod also works in singleplayer.

Features

• Virtual currency (number balances stored per player) or physical currency (an item such as diamonds used as money).
• Server shop GUI with categories, pagination, per-item buy/sell prices, shift-click bulk buy/sell and a configurable purchase tax.
• Player chest shops: attach a sign to a chest to sell its contents, with ownership protection so other players cannot open shop chests.
• Player-to-player payments, balance leaderboard and held-item price checks.
• Command rewards: any shop entry can run console commands on purchase, for example giving claim blocks or a LuckPerms rank, with or without handing over a physical item.
• New accounts automatically receive the configured starting balance. Balances are saved to disk on every change and on server shutdown.
• A daily cap on how much each player can earn from selling, to slow inflation.

Commands

Player commands

Command	Permission node	Description
/bal [player]	viper-economy.command.bal (viper-economy.command.bal.others to check others)	Show your balance, or another online player's balance
/pay <player> <amount>	viper-economy.command.pay	Send money from your balance to another player
/baltop	viper-economy.command.baltop	Show the top 10 balances
/withdraw <amount>	viper-economy.command.withdraw	Convert balance into physical currency items (physical mode only)
/topup <amount>	viper-economy.command.baltop	Convert physical currency items from your inventory into balance (physical mode only)
/worth	viper-economy.command.worth	Show the shop buy and sell price of the item in your main hand
/buy <item> [amount]	viper-economy.command.buy	Buy an item from the server shop by id, for example /buy minecraft:diamond 5
/sell <item> [amount]	viper-economy.command.sell	Sell an item to the server shop by id
/sell hand [amount]	viper-economy.command.sell	Sell the stack in your main hand, optionally capped to an amount
/sell all [amount]	viper-economy.command.sell	Sell every matching item of the held type in your inventory
/servershop	viper-economy.command.servershop	Open the server shop GUI

Players can also use the shop GUI directly: left-click buys 1, shift-left-click buys a stack, right-click sells 1, shift-right-click sells everything of that item.

Admin commands (server operators only)

Command	Description
/givemoney <player> <amount>	Add money to a player's balance
/takemoney <player> <amount>	Remove money from a player's balance (fails if they cannot cover it)
/setmoney <player> <amount>	Set a player's balance to an exact value
/resetmoney <player>	Reset a player's balance to the configured starting balance
/ecolog	Show the active economy settings and the number of stored accounts

Configuration

All files live in config/viper-economy/ on the server. config.json is created with defaults on first start. prices.json (500+ entries) is auto-deployed on first start; every registered item appears in the shop, with unpriced items listed as catalog-only until you set prices.

config.json

Field	Default	Description
economyMode	"VIRTUAL"	"VIRTUAL" stores balances as numbers. "PHYSICAL" counts currency items in inventories instead.
physicalCurrencyItem	"minecraft:diamond"	Item id used as money when economyMode is "PHYSICAL".
startingBalance	1000.0	Balance granted to new accounts on first join. Also used by /resetmoney.
dailyAmount	100.0	Reserved. Currently only displayed by /ecolog and not granted automatically.
dailySellLimit	10000.0	Maximum total sell value each player can earn per day. Applies to the shop GUI and /sell.
taxRate	0.1	Fraction added on top of every server shop purchase (0.1 = 10 percent).
pvpBalanceLossPercentage	0.0	Reserved. Currently has no effect.
standaloneCommands	true	Reserved. Currently has no effect; command access is controlled by the permission nodes above (all default to every player, level 0).
standaloneAdminCommands	false	Reserved. Currently has no effect; admin commands always require operator status.
scoreboardEnabled	true	Reserved. Currently has no effect; no scoreboard is rendered.
serverShopEnabled	true	Set to false to disable /servershop and the shop GUI.
showAllItemsCategory	true	Set to false to hide the All Items category from /servershop. Curated categories stay visible.

prices.json

Each shop entry maps an item id to its category, transaction stack size, buy price and sell price. A price of 0 means that direction is disabled.

"minecraft:diamond": {
    "category": "gems",
    "stack": 64,
    "unit_buy": 100.0,
    "unit_sell": 50.0
}

Field	Description
category	Category key. Must exist under categories; unknown or blank values fall back to the All Items category.
stack	Bulk quantity for shift-click buying in the GUI.
unit_buy	Price to buy one from the server shop. 0 means not purchasable. Tax is added on top at purchase time.
unit_sell	Price the server shop pays for one. 0 means not sellable. Counts toward the daily sell limit.
commands	Optional list of console commands run when the entry is bought. {player} is replaced with the buyer's name.
give_item	Optional. Set to false so buying runs only the commands without giving a physical item. Defaults to true.

Categories map a key to a display name and a display item:

"rewards": {
    "name": "Server Rewards",
    "display_item": "minecraft:nether_star"
}

Command rewards (claim blocks, ranks, kits)

"minecraft:nether_star": {
    "category": "rewards",
    "stack": 1,
    "unit_buy": 5000,
    "unit_sell": 0,
    "give_item": false,
    "commands": ["claimblocks {player} add 1000"]
}

"minecraft:enchanted_golden_apple": {
    "category": "rewards",
    "stack": 1,
    "unit_buy": 10000,
    "unit_sell": 0,
    "give_item": false,
    "commands": ["lp user {player} parent add vip"]
}

Commands run as console with full permissions, and the buyer sees a "Rewards applied!" message. Reward entries show a "Grants perks on purchase" lore line in the shop. Works from both the GUI and /buy.

Chest shops

Player-run shops that trade items for balance money. No sign writing is needed: you build the chest and sign, then link them with a command.

Setup, step by step

1. Place a chest (single or double) and attach a wall sign directly to it. Standing signs do not work.
2. Put at least one of the item you want to trade into the chest. The sold item is auto-detected from the first non-empty chest slot.
3. Look at the sign (within 5 blocks) and run /shop create buy <price> to sell to customers, or /shop create sell <price> to buy from customers.
4. The sign is rewritten automatically and the shop opens for business. Restock the chest as it sells out.

The /shop commands

Command	Parameter	Description
/shop create buy <price>	price: minimum 0.01, per single item	Look at a wall sign on a stocked chest to open a selling shop. Customers buy 1 item per click for price.
/shop create sell <price>	price: minimum 0.01, per single item	Look at a wall sign on a chest to open a buying shop. Customers sell you 1 item per click and receive price from your balance.
/shop remove	none (look at the sign)	Delete your targeted shop. Only the owner can use it.
/shop info	none (look at the sign)	Show owner, type, price and item id of the targeted shop.
/shop list	none	List all of your shops with type, item and price.
/shop admin <player> remove	player: any online player; look at the sign	Operator-only (permission level 2 or higher). Removes the targeted sign's shop regardless of owner.

Creating and removing your own shops needs no special permission. One sign and one chest can each belong to only one shop, and an empty chest cannot become a shop.

Sign layout (written automatically)

Line	Content	Description
1	[BUY] or [SELL]	Shop type, set by the create command.
2	Item name	Display name of the traded item, detected from the chest.
3	$<price>	Price per single item.
4	Owner name	Shop owner's name, truncated to 14 characters.

How trading works

• BUY shop: the customer must have enough balance, then 1 item leaves the chest stock, 1 item is given to the customer, the price moves from the customer to the owner (credited even while the owner is offline), and the sign-side display updates.
• SELL shop: the customer must carry the traded item, the chest must have a free slot, and the owner must afford the price. Then 1 item moves from the customer into the chest and the price moves from the owner to the customer.
• Every click trades exactly 1 item. There is no sales tax and no daily sell limit on chest trades.
• Only the owner and server operators can open a shop chest. Other players are blocked with a message when they try.
• Shops are stored in config/viper-economy/shops.json and survive restarts.

Installation

1. Install Fabric Loader (0.14.21 or newer on 1.21.x, 0.19.3 or newer on 26.x) and Fabric API for your Minecraft version. Use Java 21 for 1.21.x and Java 25 for 26.x.
2. Download the file below that matches your Minecraft version (1.21.x, 26.1, 26.2 or 26.3).
3. Put the jar in the server mods folder and start the server once. This generates config/viper-economy/config.json and prices.json.
4. Edit the prices to taste. Most changes apply without a restart.

Notes

• Storage is plain JSON files under the server config folder. No database needed.
• The 1.21.x build runs on 1.21 through 1.21.11.
• Requires Fabric API (any version for your Minecraft release).