What is a crypto exchange?

Written and maintained by the BTCNATOR editorial team • Last updated September 8, 2026 • How we research

Quick answer

A crypto exchange is a service for buying, selling and trading cryptocurrencies. A centralised exchange (CEX) is a company that holds your funds, matches trades on its own systems, and usually requires an account and identity verification. A decentralised exchange (DEX) is a smart contract you trade against directly from your wallet, with no account and no custody. Each model trades convenience and support against control and self-responsibility.

Centralised exchanges (CEX)

You deposit funds, which the exchange holds on your behalf, and you trade using its order book. Benefits: easy fiat on-ramps, deep liquidity, customer support, and account recovery. Costs: you are trusting the company to stay solvent, secure and available; it can freeze accounts or restrict withdrawals; and "not your keys, not your coins" applies while funds sit on the platform.

Decentralised exchanges (DEX)

You connect a self-custody wallet and swap tokens against liquidity pools via a smart contract. Benefits: you keep custody, no sign-up, access to almost any token on that chain. Costs: no support or recovery, exposure to contract bugs and scam tokens, and network fees on every trade. See What is a DEX? for detail.

Choosing between them

Buying crypto with a bank card for the first time → a regulated CEX is usually the practical route.
Swapping tokens while keeping custody, or trading a token not listed anywhere central → a DEX.
Holding for the long term → withdraw to a wallet you control regardless of where you bought.

Key facts

CEX = company holds funds, account required, support available.
DEX = smart contract, self-custody, no account, no support.
Funds left on any exchange are exposed to that platform’s solvency and security.
Withdrawing to self-custody removes platform risk but shifts all responsibility to you.
Fees, supported assets and withdrawal limits vary widely between exchanges.

Risks and limitations

Centralised exchanges have failed, been hacked, or frozen withdrawals — do not store more than you need to trade.
Account access can be lost to phishing, SIM-swap or credential theft; use strong 2FA (an authenticator app or hardware key, not SMS).
On a DEX, scam tokens and malicious approvals are common.
Regulatory changes can restrict access to an exchange in your country.

FAQ

Is my money safe on a crypto exchange?

On a centralised exchange, your funds are only as safe as that company. Exchanges have been hacked and have gone insolvent. For anything you are not actively trading, withdraw to a wallet you control.

Do I need ID to use an exchange?

Most centralised exchanges require identity verification. Decentralised exchanges do not, because there is no account — you connect a wallet.

What does "not your keys, not your coins" mean?

If a third party holds the private keys (as a centralised exchange does), you are relying on them to honour your balance. Only self-custody gives you direct control.