Balancer V3 is the generation that moved the hard parts of an AMM into one Vault and left pools as nothing but math. A pool is a contract that answers one question, given these balances what does this trade return, and the Vault does everything else: custody, accounting, fees, and the rate scaling that lets a pool hold yield-bearing tokens without leaking their yield to arbitrage.

That split is what makes it composable. Boosted pools hold ERC-4626 wrappers so idle liquidity earns lending yield while it waits to be traded. Weighted pools keep a basket at its target allocation, stable pools trade pegged assets along a curve that stays flat where the peg is, and hooks let a pool attach its own logic to a swap or a deposit. Every pool settles through the same Vault, so one transaction can route across many of them while only net balances ever move.

None of that runs a position. A boosted pool's balances drift as rates accrue, the fee a pool charges is set by governance on its own schedule, and a liquidity provider's share of a basket changes composition every block someone trades against it. Adding liquidity at the right ratio, taking it out into the asset you actually want, and doing either when the pool's state says so is work that waits on whoever is holding the keys.

Every number the Vault keeps about a pool is a step in a plug: its balances, the rates it scales them by, the swap fee it charges, and the quote for any size. A swap, a deposit, or a withdrawal runs when a condition is met rather than when a person is awake.

Liquidity pulled the block a pool's balance tips past your line. A swap that waits for the quote you set. A basket topped up from idle balances on a schedule nobody has to remember.

The pools that compound on Balancer are already run this way. The difference between two depositors in the same pool is the one who acts by rule.