Decentralized exchanges (DEX) are a type of cryptocurrency exchange, which allow for either direct peer-to-peer, or Automated Market Maker (AMM) liquidity pool cryptocurrency transactions to take place without the need for an intermediary. The lack of an intermediary differentiates them from centralized exchanges (CEX).

In transactions made through decentralized exchanges, the typical third party entities which would normally oversee the security and transfer of assets (e.g. banks, stockbrokers, online payment gateways, government institutions, etc.) are substituted by a blockchain or distributed ledger. Some common methods of operation include the use of smart contracts or order book relaying –although numerous other variations are possible, with differing degrees of decentralization.

Because traders on a decentralized exchange often do not need to transfer their assets to the exchange before executing a trade, decentralized exchanges reduce the risk of theft from hacking of exchanges, but liquidity providers do need to transfer tokens to the decentralized exchange. Decentralized exchanges are also more anonymous than exchanges that implement know your customer (KYC) requirements.

As of 2018, there were signs that decentralized exchanges had been suffering from low trading volumes and reduced market liquidity. The 0x project, a protocol for building decentralized exchanges with interchangeable liquidity, attempted to solve this issue.

As of mid‑2025, weekly trading volume on decentralized exchanges (DEXs) averaged around $18.6 billion, with more than 9.7 million unique wallets interacting with DeFi protocols.

Due to a lack of KYC processes, and no way to revert a transaction, users are at a loss if they are ever hacked for their passwords or private keys. Liquidity providers staking in DeFi protocols may also suffer an impermanent loss when the relative value of the deposited token pair has shifted by the time the deposit is withdrawn.

Although liquidity pool DEX are the most widely used, they may have some drawbacks. The most common problems of liquidity pool DEXes are market price impact, slippage, and front running.

Price impact arises from the design of automated market makers: the larger the trade, the greater its effect on the pool's prevailing price. For example, if the constant product AMM is in use, every deal must keep the product xy = k constant, where x and y are quantities of two cryptocurrencies (or tokens) in the pool. Price impact is non-linear, so the larger is the input amount Δx, the lower is the final ratio y / x that gives an exchange price. The problem is mostly significant for relatively large deals versus the liquidity pool size.

Decentralized Finance protocols exhibit varying degrees of decentralization, which largely depend on the architecture of their underlying smart contracts and external dependencies. When the protocol's smart contracts are deployed statically, such that the protocol's logic cannot be altered and no access-restricted functions are present, they may potentially function as neutral infrastructure. Conversely, if the smart contracts are upgradeable or permit the modification of key parameters, or if key functions are restricted to a specific set of users, this neutrality can be compromised.

A decentralized exchange can still have centralized components, whereby some control of the exchange is still in the hands of a central authority. The governance of a DeFi platform, typically as part of a Decentralized Autonomous Organization, is done through tokens that grant voting rights and are distributed amongst participants. However, the majority of these tokens are often held by few individuals and are rarely used to vote.

In July 2018, the decentralized exchange Bancor was reportedly hacked and suffered a loss of $23.5 million in assets before freezing funds. In a Twitter tweet, Charlie Lee, the creator of Litecoin, spoke out and claimed an exchange cannot be decentralized if it can lose or freeze customer funds.