Choosing where to trade crypto isn't just about fees — it's a decision about who controls your funds and how a trade actually gets matched. Centralized exchanges (CEXs) like Binance and Coinbase run internal order books and hold your assets in custody. Decentralized exchanges (DEXs) like Uniswap execute trades via smart contracts, and you keep custody the entire time.
Core Differences
| Factor | CEX | DEX |
|---|---|---|
| Custody | Exchange holds your assets | You hold assets in your own wallet |
| Order matching | Central limit order book | AMM pools or on-chain order books |
| Speed | Milliseconds | Seconds to minutes (block time) |
| KYC | Usually required | None |
| Failure mode | Exchange insolvency/hack (FTX 2022) | Smart contract exploit, MEV, front-running |
Liquidity and Slippage
Top-tier CEXs offer far deeper order books for major pairs, meaning a $500,000 market order in BTC/USDT moves the price far less on Binance than the equivalent swap would move a Uniswap pool. DEX liquidity is concentrated in a handful of blue-chip pools and thins out fast for smaller-cap tokens, where slippage of 1-5% on a modest trade size is common.
Price Impact ≈ Trade Size / (Trade Size + Pool Liquidity) [constant-product AMM approximation]MEV: A DEX-Specific Risk
Because DEX transactions sit in a public mempool before being confirmed, bots can see your pending swap and 'sandwich' it — buying just ahead of your order to push the price up, then selling right after, capturing the spread you effectively paid. This doesn't exist on a CEX, where the matching engine is private and instantaneous.
FTX held roughly $8 billion in customer deposits it could not return in November 2022. 'Not your keys, not your coins' is a cliché precisely because it has been proven true, repeatedly, at massive scale.
Practical Guidance
- ▸Use CEXs for size, speed, and leverage — but never hold more on an exchange than you're willing to lose entirely.
- ▸Use DEXs for new-token access, censorship resistance, and self-custody — but budget for slippage and MEV protection (private RPCs, slippage limits).
- ▸Withdraw trading profits from CEXs regularly rather than letting balances accumulate.