What Is a Liquidity Pool? AMMs and DeFi Trading Explained

Olvis Gil · October 31, 2026 · 8 min read

Every time you swap tokens on a decentralized exchange, a liquidity poolmade it possible. No order book, no market maker — just a smart contract holding tokens that anyone can trade against, priced by math instead of matching orders. It is the mechanism DeFi runs on.

How a pool works

Users called liquidity providers deposit a token pair — for example equal values of USDC and XLM — into a smart contract. Traders swap against that pool: put USDC in, take XLM out. The pool's AMMsets the price automatically from the token ratio (the classic formula is x·y=k — sell one token and it gets scarcer, so its price rises). Every trade pays a small fee, typically ~0.3%, distributed to providers pro-rata.

Where the yield comes from — and the catch

Provider yield is real: you earn a share of every trade through your pool. The catch isimpermanent loss — when prices move, the pool automatically rebalances your position to hold more of the token that fell and less of the one that rose. On a big price move you can end up worse than just holding. The yield compensates you for this risk — on volatile pairs, sometimes not enough.

Liquidity pools on Stellar

Stellar has native liquidity pools built into the protocol itself (not just smart contracts) — any asset pair can have a pool, fees route to providers, and swaps can execute against pools or the built-in order-book DEX, whichever gives the better rate. Path payments even chain multiple conversions automatically, so a USDC→EURC payment can route through pools mid-transaction.

The honest take

Pools are a genuine innovation — they made on-chain trading work without market makers. But "provide liquidity and earn" is not passive income: impermanent loss, scam pools with worthless tokens, and thin liquidity all eat returns. Established pools with real volume and stablecoin pairs are the sensible starting point; triple-digit APY pools are where beginners learn the risk lesson.

Keep learning

Liquidity pool term ·What is an AMM? ·Impermanent loss ·DeFi for Beginners ·DeFi on Stellar: Soroswap

Frequently asked questions

What is a liquidity pool in simple terms?

A liquidity pool is a smart contract holding a pair of tokens — say USDC and XLM — that users can trade against directly. Instead of matching buyers with sellers, the pool’s algorithm sets the price from the ratio of tokens inside.

How do liquidity providers earn money?

Every trade through the pool pays a small fee (typically 0.3%) that is distributed to liquidity providers proportional to their share. On busy pools this adds up; on quiet ones it does not cover the risks.

What is impermanent loss?

When the price ratio of your deposited tokens changes, the pool rebalances your share — you end up with more of the token that fell and less of the one that rose. Compared to just holding, you can be worse off. It is called impermanent because it reverses if prices return to your entry ratio — but often they do not.

Are liquidity pools safe?

The mechanism is sound but risks are real: smart-contract bugs, scam pools with fake tokens, impermanent loss, and thin liquidity causing slippage. Stick to established protocols and audited pools.

Share this article

Olvis Gil

Founder of EduNode — an educational platform teaching blockchain development on Stellar, Ethereum, Soroban, and beyond.