The refill — how a machine earns and burns

Every cabinet has a REFILL PRESSURE gauge: a bar that fills as the machine earns, and a promise about what happens when it's full — the machine buys its own coin back and burns it. This page explains exactly what fills that bar, in which currency, and why.

Where a machine's earnings come from

Every swap in a cabinet's pool pays a small fee, and the floor's fee plumbing delivers all of a pool's fees in one currency: the coin the cabinet is paired with (fees collected in other coins are auto-converted on the way — we verified this on-chain, in both trade directions). So each machine earns exactly one thing:

• Every cabinet trades against WETH, the mother included — one pair for the whole floor, so no cabinet has to read another cabinet's pool to know what it earned. The floor counts what it earns in sats, so a bar means the same thing in a month as it does today.
• The bar's full mark is 50 basis points of that pool's own depth, read live from the pool every pass — a deep pool has a higher bar than a thin one, and no number is typed anywhere. (It used to be a fixed setting, and when the floor's pair changed the setting did not: the mother's bar read "24 sats" against a real target of 645,900. A live read cannot go stale.)
• A pool earns only what is in it. A cabinet's pool holds its coin and WETH, so those are the only two things its fees can arrive as. Your ETH still gets there — the router wraps and routes it — but by the time it reaches the pool it is the pair.

(Until 09-04 the mother traded against Bitcoin and every other cabinet traded against COIN-OP, which is why older screenshots show two currencies and a change machine between them. One pair replaced both.)

One machine, one currency, one gauge. No hidden streams.

What fills the bar

The bar fills with the machine's pair currency — the coin it will spend on its own buyback:

• Mother machine: the pot holds the pair — WETH — and the floor counts it in sats: shown in sats against a sats target.
• Paired cabinets: the pot's COIN-OP, shown as a plain COIN-OP amount against a COIN-OP target.

The numbers are live on-chain balances, never estimates. That's also why a paired cabinet's bar is counted in COIN-OP rather than "converted to dollars": pricing it would require a spot quote that can be manipulated for a moment. A hard token count can't lie.

The target scales with the machine. The bar's target is the larger of a published minimum and 0.5% of the pool's own depth on the pay side, read live from the pool: a bigger pool needs a bigger refill to move it, and the minimum keeps a tiny pool from firing dust. The cabinet page shows the live target — the same number the keeper fires on.

"Ready to burn" — the line under the bar

Sometimes the pot ends up holding the machine's own coin — for example when an expired prize round's unclaimed coins are swept back to REFILL. Those don't need to be bought — they're the very thing the buyback exists to acquire. They wait under the bar as "+ X in the pot, ready to burn" and burn together with the bought-back coins when the bar fills.

One rule with no exceptions: the machine never sells its own coin. Its own coin has exactly one exit from the pot, and it's the furnace.

When the bar fills

• Mother machine: the pot's WETH (counted in sats) market-buys COIN-OP in its own pool → everything burns.
• Every other cabinet: the pot holds the cabinet's own pay currency — WETH, the floor's one pair — and buys the cabinet's coin in one hop through its own pool → everything burns.

Note what happens to the COIN-OP a paired cabinet spends: it isn't burned — it lands inside the pair's pool as depth, like any buy. So one refill firing does two good things at once: the cabinet's coin burns (supply down), and the mother coin ends up working in liquidity (depth up). Burning the mother coin itself is the mother machine's own job.

Every burn feeds the COINS EATEN counter. The floor eats; the float shrinks.