Crypto trades happen on two broad kinds of venue: centralized exchanges (CEXs) and decentralized exchanges (DEXs). They differ in who holds your funds, how prices are set, what you can trade and what can go wrong. Neither is safer in every respect. Each one moves risk to a different place.
What Is a Centralized Exchange
A centralized exchange is a company that runs a trading platform. Binance, Coinbase and Kraken are well-known examples. You open an account, verify your identity and deposit funds. From that point the exchange holds the assets, and your balance is an entry in its database. You do not control the private keys.
Trades are matched on an order book. Buyers post bids, sellers post asks, and the exchange's matching engine pairs them. Nothing touches the blockchain until you deposit or withdraw.
Centralized exchanges typically offer:
- Deposits and withdrawals in regular currency by bank transfer or card
- Deep liquidity and tight spreads on major pairs
- Limit, stop and other order types, plus margin and futures in some regions
- Customer support and account recovery if you lose a password
- Identity checks (KYC) required by regulation in most jurisdictions
The central risk is custody. If the exchange is hacked, freezes withdrawals or becomes insolvent, customers can lose access to their assets. Mt. Gox failed in 2014 after losing customer bitcoin. FTX filed for bankruptcy in November 2022 after customer funds were misused. The SEC's investor.gov crypto asset resources warn that crypto platforms may lack the protections investors are used to with registered brokers and exchanges.
What Is a Decentralized Exchange
A decentralized exchange is a set of smart contracts on a blockchain. Uniswap, Curve and PancakeSwap are examples. You connect a wallet, approve a token and swap. The assets stay in your wallet until the trade executes, and settlement happens on-chain where anyone can verify it.
Most DEXs use an automated market maker (AMM). Each market is a pool holding two or more tokens, supplied by liquidity providers who earn trading fees. A formula sets the price from the ratio of tokens in the pool. The Uniswap documentation explains the model. Some DEXs, mainly those for perpetual futures, use order books instead.
Decentralized exchanges typically offer:
- Self-custody during the whole process
- No account in most cases, only a wallet
- New tokens available as soon as someone creates a pool
- Transparent, on-chain settlement
- Direct connection to lending, staking and other DeFi protocols
The risks are different. There is no support desk and no way to reverse a mistake. Smart contracts can have bugs. Anyone can list a token, so fraudulent tokens are common. Trades in small pools suffer price impact, and bots can trade around your order to give you a worse price. You also pay a network fee, called gas, for each transaction.
Key Differences
- Custody: a CEX holds your funds. On a DEX they stay in your wallet.
- Identity: a CEX requires verification. A DEX usually needs only a wallet.
- Pricing: a CEX uses an order book. Most DEXs use liquidity pools.
- Fiat access: a CEX connects to banks. A DEX only trades crypto for crypto.
- Token range: a CEX lists tokens after review. A DEX lists anything, good or bad.
- Fees: a CEX charges trading and withdrawal fees. A DEX charges a swap fee plus gas, which varies with network demand.
- Recovery: a CEX can reset a password. Nobody can restore a lost seed phrase.
- Transparency: DEX trades and reserves are public on-chain. CEX reserves depend on the company's own disclosures.
What Each Costs
On a centralized exchange, look at the trading fee, the spread and the withdrawal fee. Simple "buy now" screens often cost more than the same exchange's advanced trading view.
On a DEX, add up the pool's swap fee, any interface fee, gas and price impact. On Ethereum mainnet, gas can make small trades uneconomic. On Layer 2 networks and other low-fee chains, gas is usually a few cents.
Which One Fits Which Job
A CEX is the usual starting point for turning regular currency into crypto, and for trading large amounts of major coins at tight spreads. It suits people who want support and are not ready to manage keys.
A DEX suits people who already hold crypto in a self-custody wallet, want tokens that are not listed on centralized platforms or use other DeFi protocols. It demands more care from the user.
Many people use both: a CEX as the bridge to their bank, and a wallet with DEXs for everything on-chain.
Common Mistakes
- Leaving long-term holdings on an exchange: balances you do not plan to trade are exposed to exchange failure for no benefit.
- Skipping two-factor authentication: use an authenticator app, not SMS, and set a withdrawal address allowlist where available.
- Buying the wrong token on a DEX: fake tokens copy real names. Confirm the contract address from the project's official site.
- Unlimited approvals: approving a contract to spend unlimited tokens stays in force until you revoke it.
- High slippage settings: these invite bots to take the difference.
- Withdrawing on the wrong network: sending to an address on a chain the recipient does not support can lose the funds.
The CFTC's customer advisory on virtual currency trading covers further risks that apply to both types of venue.
Nothing in this article is financial advice.
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The exchanges page lists exchanges to compare. The DEX page shows active liquidity pools with their volume and liquidity, which helps you judge pool depth before a swap. The converter gives a reference rate to check against any quote you are offered.