Not financial, legal, or tax advice. Providing liquidity carries risk of loss, including impermanent loss.
A liquidity pool is a shared pot of two or more tokens, locked in a smart contract, that lets people trade between those assets without needing a traditional buyer and seller matched directly. They're the foundation that makes decentralized trading possible, central to \[pillar hyperlink: What Is DeFi\].
The concept
Instead of an order book matching buyers and sellers, a liquidity pool holds reserves of paired assets, and trades happen directly against that pool using a pricing formula, adjusting automatically as trades occur.
Liquidity providers
Anyone can typically become a liquidity provider by depositing an equal value of both assets in a pool, earning a share of the trading fees generated by that pool in return.
Impermanent loss
If the price of the two pooled assets diverges significantly after you've deposited them, you can end up with less value than if you'd simply held the assets separately, a risk known as impermanent loss and one of the most important concepts to understand before providing liquidity.
Risks
Beyond impermanent loss, risks include smart contract bugs and the pool's underlying assets losing value. These pools are the core mechanism behind What Is a DEX, and the same risk considerations covered in Staking vs Yield Farming apply here.