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

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)

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

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
}

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

1. Place a chest and attach a sign to it.
2. Write the shop type, item, price and amounts on the sign lines.
3. Stock the chest. Other players click the sign to buy; only the owner (or an operator) can open the chest.

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).