Docs

Every round lasts 90 seconds, of which the first 60 accept wagers. You pick any of the 25 seams and set an amount per tile. When betting closes, a drand beacon selects one seam, and everyone who committed to it splits the pot in proportion to what they staked there.

The randomness is requested after betting closes and comes from a beacon that had not yet been published at request time, so nobody — including us — can know the outcome while wagers are still open. If a beacon fails to arrive, the round retries up to 3 times and then refunds every wager in full.

A round nobody wins rolls its pot into the next one. A round too small to pay for its own randomness is refunded rather than drawn — which is why the round total matters more than the per-tile minimum: 0.0834 USDC has to be committed across the grid, by you or by everyone together, before the draw can happen at all. The wager floor of 0.27 USDC per tile sits above that, at the point where a single-tile round covers its own randomness and keeper costs rather than being subsidised.

Round length

90s

Betting window

60s

Seams

25

Minimum per tile

0.27 USDC

Minimum per round

0.0834 USDC total

Winning a round pays USDC immediately and also credits mined GRID. Mined GRID is not in your wallet yet: it sits in the vault until you refine it.

Refining costs a fee that starts at 20% and decays to 10% over 24 hours of holding. The fee is not burned — it is paid out as dividends to everyone who has not yet refined. Holding longer costs you less and earns you more of what impatient miners pay.

You can also refine straight into a permanent veGRID lock at no fee at all, which skips the cash-out entirely and starts earning USDC instead.

Refining fee

20% → 10%

Decay window

24h

Fee goes to

miners who have not refined

GRID has a hard cap of 500,000 and is released by mining. The cap is enforced against cumulative minting, so burning never creates room to mint more.

Genesis was a one-time 1,000 GRID: 88% paired into the liquidity pool, 8% vested to the team, and 4% to the growth fund.

Each settled round mints 1.12 GRID — 1 to the winning seam, 8% to the team and 4% to the growth fund, both on top rather than taken out of the miner's share.

The team share is burned and replaced with a permanent, non-transferable veGRID position. The tokens stop existing; what remains is a claim on USDC revenue that can never be sold or withdrawn. So the circulating effect of each round is about 1.04 GRID, and total supply drifts below total minted over time.

Hard cap

500,000 GRID

Genesis

1,000 GRID (88 / 8 / 4)

Minted per round

1.12 GRID

→ miners

1 GRID

→ team

8%, burned into a permanent lock

→ growth fund

4%

Max rounds per day

960

Winners keep 88% of the pot. The remaining 12% is split three ways, all paid in USDC, all automatic.

Winners

88%

veGRID stakers

8%

Payload jackpot

2%

Buyback and burn

2%

The buyback share buys GRID on the open market and burns it. There is no treasury holding it and no address that could move it later — the supply reduction is provable rather than promised.

Buying or selling GRID on the protocol pool pays 2%, charged inside the pool itself. It is collected in GRID, sold for USDC once enough accumulates, and added to the Payload. Trading the token grows the jackpot.

The tax applies only to pool trades. Wallet-to-wallet transfers are untouched, as are the protocol's own contracts, and adding or removing liquidity is never taxed.

Buy tax

2%

Sell tax

2%

Destination

100% Payload

Hard cap on the rate

2%, enforced in the contract

The growth fund receives 4% of every newly minted GRID, sells it for USDC, and recycles the proceeds: half to the Payload, half to liquidity stakers.

It is a contract, not a wallet. It has no withdraw, rescue or sweep function, so nobody — including the protocol owner — can take funds out of it. The only path out is the split above.

Receives

4% of new GRID

→ Payload

50%

→ LP stakers

50%

Withdrawable by anyone

no

Locking GRID mints a veGRID position that earns 8% of every round's pot, paid in USDC rather than in more GRID. Longer locks carry more weight, so rewards are shared by voting power rather than by amount alone.

Time locks run up to 120 days and return your GRID when they expire. A permanent lock burns the GRID outright and never returns it, in exchange for the maximum weight and a perpetual claim on revenue. Weight changes take effect from the next 1-hour epoch, which is what stops anyone locking moments before a payout to capture it.

Earns

8% of every round, in USDC

Max time lock

120 days

Permanent lock

burns the GRID, keeps the revenue claim

Epoch

1h

The Payload is a jackpot fed by 2% of every round and by the entire trading tax. Each settled round has a 625-to-one chance of triggering it, paying 80% of the pot to that round's winners.

The odds and payout for a round are frozen when its randomness is requested — before any outcome is knowable — so they cannot be changed once a round is in flight.

Odds

1 in 625 per settled round

Payout

80% of the pot

Funded by

2% of rounds + 100% of trading tax

Insurance lets you take a position on whether the Payload will trigger during a block of 100 rounds. Buy YES if you think it will, NO if you think it will not. Sets are priced from the Payload odds plus a house edge, and you can cash out early at a quoted price while the set is still running.

Set size

100 rounds

Minimum stake

0.5 USDC

House edge

3% YES / 10% NO

Buying GRID through the lottery earns tickets as well as tokens. A draw runs every 1 hour and has a 1,000-to-one chance of paying the whole pot to one ticket holder, weighted by tickets held. When it misses, the pot rolls forward.

Odds

1 in 1,000 per draw

Draw interval

1h

Minimum buy

0.01 USDC

Coal runs on Arc, chain ID 5042, where USDC is the gas token — so you pay fees and place wagers in the same asset. Connect any EVM wallet; if it is on another network, the app will offer to switch.

every contract, wager and payout is public on Arc Explorer.

Coal is a game of chance played with real money. Rounds are settled by public randomness and the odds are stated above; the house edge is the 12% fee, which funds stakers, the jackpot and the buyback. You can lose what you wager.

GRID is a reward token, not an investment product. Its price comes from a market that anyone can trade against, and a thin market moves sharply. Nothing here is a promise of return.