An economy is three plugins and one design decision. The plugins are easy. The design decision — where money leaves the world — is the one that determines whether prices still mean anything in six months.
The three pieces
- Vault
Not an economy itself. It is the adaptor other plugins talk to, so a shop plugin does not need to know which economy plugin you chose. Almost everything expects it to be present.
- An economy plugin
This one actually holds the balances. It registers with Vault, and from then on everything else asks Vault rather than asking it.
- A shop or auction plugin
Where money moves between players and between players and the server. This is where your design decision lives.
The decision: where does money come from and go?
Every economy has faucets, where money enters, and sinks, where it leaves. Selling items to the server is a faucet. Buying from the server, paying for a claim, and repair costs are sinks.
Servers routinely build the faucets on day one and the sinks never. Six months later a diamond costs forty thousand, new players cannot participate, and everyone concludes «the economy is broken» — which it is, but not for a mysterious reason.
Faucets and sinks
| Faucet | Sink |
|---|---|
| Selling mob drops to the server | Buying blocks the server generates |
| Daily login rewards | Land claim costs |
| Vote rewards | Teleport or warp fees |
| Quest and job payouts | Auction house listing fees |
| Mining and farming sales | Cosmetics and ranks |
If the server buys an item at a fixed price with no limit, any farm that produces that item is a money generator, and someone will find the most efficient one within a week. Either make prices dynamic, cap daily sales, or accept that the number on everyone's balance stops meaning anything.
If players trade with each other, money circulates instead of being created. Adding a small transaction fee makes that circulation a sink too. Many of the healthiest servers have almost no server shop at all.
/balance returns a number, a shop purchase deducts it, and Vault reports your economy plugin as hooked in the startup log.