how the fee leans

The waterline

On most launchpads a dump costs the same as any other trade. On Bobbly the pool pushes back: selling into a falling price costs more, buying it costs less, and once the price is left alone the fee goes back to normal.

Push the price under its mark

Under the mark

a buy: A buy that starts here is lifted: it pays less than the base, and less the deeper it starts.
a sell: A sell that lands here is dragged: it pays more than the base, and more the deeper it lands.

Whichever way it runs, the fee is taken in ETH: out of what a buyer pays in, out of what a seller is paid.

Every pool keeps a high-water mark

The mark is the dearest a pool's token has been. A buy that takes the price to a new high takes the mark up with it.

How far the price sits under its mark is the pool's depth. At the mark the depth is nothing, and a buy and a sell both pay the base fee.

A sell is charged where it lands

A sell pays by the depth it leaves the price at. The further it drags the price under the mark, the more it pays, up to a ceiling at a full depth.

Charging a sell on the depth it found would make the first one out the cheapest, which is a reason to run. Charging it where it lands means the sell that makes the dip is the one that pays for it, and cutting a sell into pieces does not get under the rule: each piece lands deeper than the one before.

A buy is charged where it starts

A buy pays by the depth it finds. The further under its mark the price already is, the less the buy pays, down to a floor at a full depth.

So the same dip that costs more to sell into costs less to buy. The pool leans against the fall from both sides.

The mark settles

A fall is not held against a pool for ever. Every second the mark sinks a little toward the price, at a fixed pace. Leave a price alone for long enough and it becomes the mark, and everything pays the base fee again.

Nobody has to do anything for this to happen. The next trade simply finds the mark where the time has put it.

Always ETH, always one address

Every Bobbly pool is ETH against its token, and the fee is taken on the ETH side whichever way a trade runs: out of what a buyer pays in, out of what a seller is paid. It is never taken in the token.

All of it goes to one address, written into the contract when it was deployed. There is no setter that could point it anywhere else, and no second fee.

The pool's share is sunk

When a token is floated, the pool's share of its supply goes in as one position and stays. Nothing in the contracts can take liquidity out of a Bobbly pool: not the floater, not the pond, not the contract that put it there.

The ETH that buyers pay in sits under the price as a bid that belongs to nobody.

Where the figures are

The base fee, the ceiling, the floor, how deep a full depth is and how fast the mark settles are constants in the waterline’s source. They are not repeated on this site, because a copy can go stale and the original cannot: read them where they bind. The contracts and their addresses are on the Dock.