DEX vs CEX: what is the difference?
A DEX (decentralized exchange) is a crypto exchange run by smart contracts, where users trade from their own wallets; a CEX (centralized exchange) is a trading platform run by a company that holds client assets and matches orders. Under EU law a CEX needs an authorization under MiCA, while a DEX without any intermediary falls outside it.
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DEX and CEX in brief
| Terms | DEX, decentralized exchange; CEX, centralized exchange. German legal term for a CEX: Handelsplattform für Kryptowerte. |
|---|---|
| Legal source | Article 3(1)(16)(b) and (18) of Regulation (EU) 2023/1114 (MiCA): operation of a trading platform for crypto-assets. Recital 22 for fully decentralized services. |
| Date of application | MiCA applies from (Article 149(2)). |
| A number | Flows on decentralized exchanges "represent 10% of the spot volume traded of crypto-assets globally" (EBA and ESMA, ). |
| Supervisors | BaFin in Germany, FMA in Austria, FINMA in Switzerland. |
What is a crypto exchange, and what do crypto exchanges do?
A crypto exchange is a venue that brings buyers and sellers of crypto-assets together, the job a stock exchange does for shares. MiFID II defines a regulated market as a multilateral system that "brings together or facilitates the bringing together of multiple third-party buying and selling interests in financial instruments". MiCA uses almost the same wording: Article 3(1)(18) defines the operation of a trading platform for crypto-assets as "the management of one or more multilateral systems" that brings together "multiple third-party purchasing and selling interests in crypto-assets".
ESMA sorts crypto exchanges into two categories, CEXs and DEXs. A CEX has "a central authority or operator" and works in a way "comparable to traditional exchanges". ESMA counted more than 650 crypto exchanges worldwide in public sources, of which more than 400 would qualify as DEXs (ESMA, ).
What is a DEX, and how does DEX trading work?
A DEX is an exchange whose trading logic sits in smart contracts on a blockchain. ESMA's definition: DEXs "rely on smart contracts for peer-to-peer trading" and allow non-custodial trading, "meaning that they do not require users to entrust them with the control of their assets for trading". A DEX is one application of DeFi, so defi vs dex compares a whole field with one of its tools.
DEX trading comes in two forms. Order book exchanges keep an order book, often run by an operator off the chain, and use the blockchain for settlement. Automated market makers (AMMs) hold liquidity pools and set the price by a formula; ESMA notes that AMMs "now dominate". Because DEXs do not support fiat money, every trading pair is crypto against crypto, often a stablecoin. How pools work is explained on the page What is a liquidity pool?
How do a DEX and a CEX compare?
A DEX and a CEX differ in who runs the venue and who holds the assets.
| Feature | DEX | CEX |
|---|---|---|
| Operator | Smart contracts | A company |
| Custody | Users keep their assets in their own wallets | The platform holds client assets |
| Pricing | Mostly a pool formula (AMM) | An order book with bid and ask prices |
| Fiat money | No; crypto-to-crypto pairs only | Often, including the euro |
| Costs | Pool fees and slippage, the gap between the quoted and the paid rate | Fees set by the operator |
| Identity checks | None in the protocol | Know-your-customer checks, common at established CEXs |
| EU law | Outside MiCA when fully decentralized (recital 22) | Authorization and duties under Article 76 of MiCA |
DEX vs CEX volume: which is larger?
CEXs carry most of the volume. ESMA found that "more than 80% of the reported spot trading volumes is attributable to the 10 largest exchanges, all being CEXs except one", the exception being Uniswap. After the collapse of FTX in November 2022, spot volume on CEXs fell slightly while volume on DEXs "remained relatively stable". The EBA and ESMA estimated in January 2025 that flows through decentralized exchanges "may exceed EUR 100 billion a month".
What are the risks of a DEX and of a CEX?
The main risk of a CEX is the operator; the main risk of a DEX is the code and the anonymity of its users. At a CEX the client depends on the company that holds the assets, and ESMA cites the misappropriation of client assets at FTX. A DEX holds no client assets, which, according to ESMA, reduces "counterparty risk vis-à-vis the exchange operator". DeFi protocols, DEXs included, still suffer exploits, and on-chain trades are slow.
The EBA and ESMA see a money laundering risk: on a DEX, crypto-assets "from potentially illegitimate sources can be processed on protocols by users who are not identified or verified". The risk falls, without disappearing, when transfers run through regulated platforms.
DEX and CEX in Germany, Austria and Switzerland
In Germany and Austria a CEX needs an authorization as a crypto-asset service provider for the operation of a trading platform, Article 3(1)(16)(b) of MiCA. BaFin supervises under section 3 of the Kryptomärkteaufsichtsgesetz, the FMA in Austria. Article 76 sets the duties, among them operating rules, a ban on dealing on own account on the platform, and the publication of bid and ask prices. A credit institution may run the service after a notification under Article 60(1), a market operator under MiFID II after one under Article 60(6), each at least 40 working days before the start. BaFin states that the definition also covers systems that only facilitate the bringing together of trading interests; the contract need not be concluded in the system (BaFin, ).
For a DEX, recital 22 of MiCA states: "Where crypto-asset services are provided in a fully decentralised manner without any intermediary, they should not fall within the scope of this Regulation." The same recital keeps activities in scope when only "part" of them is performed in a decentralised manner, so a company that runs part of a DEX, such as its front end, may still fall under MiCA. Switzerland is outside the EU, so MiCA does not apply there; FINMA supervises trading venues under Swiss law. This page gives no legal advice.
Sources
- European Securities and Markets Authority: Decentralised Finance in the EU: Developments and risks,
- European Banking Authority and European Securities and Markets Authority: Joint Report: Recent developments in crypto-assets (Article 142 of MiCAR),
- European Union: Regulation (EU) 2023/1114 on markets in crypto-assets,
- European Union: Directive 2014/65/EU on markets in financial instruments (MiFID II),
- BaFin: Merkblatt: Hinweise zu den Kryptowerte-Dienstleistungen nach MiCAR,
- Federal Republic of Germany: Kryptomärkteaufsichtsgesetz (KMAG),
- FMA: FMA takes over supervision of crypto-asset service providers in Austria,