The terms used across these docs and the StonkDrop contracts, in plain language.

The game

Drop and spin

A spin is one paid pull of the machine, and it wins exactly one prize. The app calls it a drop. You can buy several in one transaction.

Commitment

One paid transaction covering one or more spins. It fixes the gacha config and a future drand round before anyone can know the outcome, along with the pricing time.

Gacha config

The rules a spin plays by: the spin price, rarity odds, prize bands, and stock catalog. A config never changes once created. New spins use the active config, and each commitment keeps the one it was made under.

Rarity

How big a prize is, not which stock it pays. Each rarity has a probability, set in basis points, and one or more prize bands.

Prize band

The dollar range a rarity pays out. Prizes are whole cents, and every cent in the band is equally likely.

Catalog

The stock tokens a spin can pay out. Each spin draws one at random, so every stock is equally likely.

Expected value and payout rate

The expected value is the average prize per spin across all rarities. Divided by the spin price, it gives the payout rate that Stats measures the machine against.

Reserve

When you commit, the contract sets aside enough USDG to cover the biggest possible prize for every spin, so pending spins are always fully backed.

Randomness

drand round

drand's Quicknet network publishes a public random value every 3 seconds. Each commitment is bound to one round, 3 rounds (7 to 9 seconds) past the timestamp of its block, so its outcome is fixed before anyone can see it, as long as the chain's block timestamps stay within a few seconds of real time.

Beacon registry

The on-chain contract that checks drand's signature for a round and stores its random value. Anyone can submit a round.

Relayer and keeper

A relayer posts drand rounds on-chain, and a keeper settles spins. One service can do both, and anyone can run one. Neither can change a prize.

Pricing

Pricing time

The timestamp of the block a commitment lands in. Prizes are priced as of this moment, however much later they settle.

Market open and off hours

Stock pricing follows Robinhood's 24 Hour Market. On each trading day the market is open from 20:00 ET the evening before until 20:00 ET, or 17:00 ET on an early-close day. Off hours are weekends, market holidays, and the evening after an early close.

Primary price

A stock's price from its Robinhood price feed. If you commit while the market is open, every stock's primary price is recorded right then, and a stock prize is converted at it.

On-chain market price

The stock token's own price in its Uniswap pool, taken as a 15-minute average up to the pricing time. While the market is open it only checks the primary price. In off hours it becomes the price, checked against the last close.

Not to be confused with: the primary price. A token can trade away from its stock's price on-chain.

Market dislocation

The on-chain market price straying too far from the stock's reference price. When it does, the prize is paid in USDG instead of stock.

Exposure cap

A limit on how much prize value can be paid in stock at off-hours prices. It resets each time the on-chain market is shown to match the primary price closely again, which is called recovery. Before the first recovery, or once the cap is used up, off-hours prizes are paid in USDG.

Corporate action

A stock split or a similar change to what one token represents. Around one, prizes in that stock are paid in USDG.

Settlement and payout

Settlement

Paying out a spin once its drand round is published. Anyone can settle a spin, or all of a commitment's spins at once, and the prize always goes to the wallet that paid.

Prize value and payout amount

The prize value is the dollar amount won. The payout amount is what was actually transferred: stock tokens worth that value, or exactly that value in USDG.

USDG fallback

When stock can't be delivered safely, the spin is paid its exact prize value in USDG instead. That payout is final. It isn't a refund, and it isn't retried.

Settlement medium

How a settled spin was paid: in stock, or in USDG along with the reason. The Stats ledger shows it for every drop.

Optimistic reveal

Showing a prize as soon as its drand round is published, before the spin settles. The prize can't change after that, but whether it's paid in stock or USDG is only final once the spin settles.

Units

USDG

The stablecoin used to pay for spins and for USDG payouts. It has 6 decimals.

Stock token

A tokenized stock on Robinhood Chain, with 18 decimals.

WAD

A fixed-point number with 18 decimals. In prize and price values, 1e18 is one dollar.

Basis points

One hundredth of a percent: 100 bps is 1%, and 10,000 bps is 100%.