What is DEX?

Plain-English explainer · Updated 2026-05-03 · By DeFi Intel

Last reviewed 2026-05-03

Entity coverage: 16 protocols, 0 tokens, 0 chains reference this concept.

A decentralized exchange settles trades on-chain via smart contracts. Users keep custody of funds. AMM-based DEXs (Uniswap, Curve, Balancer, Aerodrome) dominate spot; CLOB-based DEXs (dYdX, Hyperliquid, Vertex) dominate perps.

How it works

Most DEXs use the automated market maker (AMM) model. Liquidity providers deposit two assets into a pool contract and receive LP tokens tracking their share. The pool prices trades with a formula — classically the constant product x × y = k — so buying one asset from the pool raises its price along a curve rather than matching against individual orders.

A swap proceeds in steps: the trader approves the token, the router contract finds a route (possibly hopping through several pools), computes the output for the input amount, and reverts the whole transaction if the result lands below the trader's slippage tolerance. A fee (often 0.05–1%) is skimmed from each trade and accrues to the pool, which is how LPs earn.

Pool prices drift, so arbitrageurs trade against them until they match external markets — this is how AMMs "discover" price. Order-book DEXs work differently: makers post bids and asks, a matching engine (on-chain or on a dedicated chain) pairs them, and only settlement is anchored on-chain. In both models the user signs from their own wallet and custody never transfers to an operator.

Why it matters

DEXs let users trade without custody risk. They have grown to ~25% of total spot crypto volume and >50% in some L2 ecosystems.

Real-world examples

Uniswap, Curve, Balancer, Aerodrome, PancakeSwap, Jupiter (Solana), Hyperliquid (perps), GMX (perps).

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Frequently asked questions

What is a decentralized exchange?

A decentralized exchange settles trades on-chain via smart contracts, and users keep custody of their funds.

How do AMM-based DEXs work?

Liquidity providers deposit two assets into a pool contract and receive LP tokens; the pool prices trades with a formula like x × y = k, and a fee (often 0.05–1%) is skimmed from each trade and accrues to the pool.

Which DEXs dominate spot and perps markets?

AMM-based DEXs such as Uniswap, Curve, Balancer, and Aerodrome dominate spot, while CLOB-based DEXs like dYdX, Hyperliquid, and Vertex dominate perps.