Guide · Basics
What Is a Liquidity Pool? The Engine Behind Every DEX Trade
Decentralized exchanges don't use an order book matching buyers to sellers — they use a shared pool of two assets that anyone can trade against directly. Here's how that actually works.
A liquidity pool is a pair of assets — say ETH and USDC — locked into a smart contract that anyone can trade against directly, instead of needing another trader on the other side of the order in real time. The pool sets its own exchange rate based on the ratio of the two assets it holds, and that ratio shifts automatically with every trade.
Anyone can become a liquidity provider by depositing an equal value of both assets into the pool, in exchange for a small share of the trading fees every swap generates. It's a genuinely different role from trading — a liquidity provider isn't betting on price direction, they're being paid for making a market available.
The tradeoff is real: contributing to a pool exposes a provider to impermanent loss (a separate concept worth understanding before providing liquidity) and, if the pool isn't locked, to the rug-pull risk covered in an earlier guide — since a large enough withdrawal by another party can move the pool's price sharply.
Understanding how a pool's ratio determines price — and how a single large trade can move it — is worth testing on Trade2Spike's spot markets before ever depositing real capital into one.