Savings
"Leave a sack of coin with the clerk, come back next week, find it heavier. The Bank pays for the privilege of holding your gold - small interest, but it never sleeps."
Yield rakamları gerçek-dünya günü (24 gerçek saat) cinsindendir. "%0.5 / day" → 24 gerçek saatte yarım coin yüzde. Compound formülü takvim tabanlı; oyun günü 4 gerçek saat olduğu için Day Cycle hızıyla karıştırma.
The Bank holds two kinds of savings positions - one for coin, one for WLD. They behave identically: deposit any amount, watch it compound every second, withdraw whenever you want.
The two positions
| Asset | Daily rate | Monthly (≈) | Yearly (≈) |
|---|---|---|---|
| Coin | 0.50% / day | +16% | +6.1× (compound) |
| WLD | 0.05% / day | +1.5% | +20% (compound) |
Why is the WLD rate so much smaller? WLD is the city's premium token - its supply is capped, and inflating yield on a finite asset would erode the whole economy. The coin yield is generous because the State prints new coin every day from quests and monster drops; savings recycles it into the system.
Yield is a sink-and-recycle mechanism, not a faucet. When you withdraw your principal + interest, the interest portion is minted at withdraw time against the city's pool of inflation budget - the same pool that funds quest rewards. See the faucets and sinks overview for the full picture.
How compounding works
The math is the standard compound formula:
balance(t) = principal × (1 + dailyRate)^days_elapsed
There is no daily cron that rolls the balance forward. Instead, the Bank stores a snapshot - your principal as of the last time you touched the position - and computes the live value on every read. Two important consequences:
- You don't need to log in for interest to accrue. If you deposit 10,000 coin and disappear for a month, you come back to ≈11,600.
- The snapshot only advances when you mutate the position (top-up, partial withdraw, or close). Until then, the live tick on the card is the projection - the snapshot in the database stays where it was.
This is why the live counter on the app card moves smoothly second-by-second - it's local extrapolation, not a server poll.
Minimums
| Asset | Minimum deposit | Minimum withdraw |
|---|---|---|
| Coin | 10,000 | 10,000 |
| WLD | 1 | 1 |
The minimum on coin used to be lower, but a 100-coin deposit at 0.5%/day accrues 0.5 coin per day - which rounds to 0 in the integer-only display. The position would feel frozen on the card. Setting the floor at 10,000 guarantees ≥1 visible coin of growth on day one, and the live tick stays honest.
Withdraw enforces the same minimum as deposit, with one exception: a close-out withdraw - one where the requested amount equals the live principal exactly - is always allowed. This is so dust positions stuck below the floor (e.g. after a partial withdraw left 8,500 coin behind) can still be cleaned up.
Deposits, withdraws, and top-ups
There is no separate "open a savings account" step:
- First deposit creates the position with the asset's standard daily rate.
- Top-up deposit settles the existing position to the current second (advancing the snapshot), then adds the new principal on top. The two are treated as one position from then on.
- Partial withdraw subtracts from the live principal; the remainder keeps compounding.
- Close-out withdraw drains the position; it disappears from the app and the next deposit starts a fresh one.
All four operations are idempotent - a double-tap won't accidentally do the action twice.
What savings isn't
- Not a fixed-term product. No CDs, no lockup, no early-withdrawal penalty.
- Not insured against the city. Yield is paid out of the inflation budget; if the broader economy collapses, so does the Bank's promise. (See the On-chain Vault doc for what is backed 1-to-1.)
- Not a way to launder gold. Every deposit and withdraw is recorded in the Activity ledger. The Municipality can read it.