What is CEX (centralized exchange)?

An exchange operated by a company that holds customer funds, matches trades, and complies with regulation.

Not yet verifiedHow we verify

3 min read

In this entry

An exchange operated by a company that holds customer funds, matches trades, and complies with regulation.

Coinbase, Kraken, and Binance are centralized exchanges. They are the main way to convert fiat currency to crypto, because they can hold a bank account, accept a card payment, and answer to a regulator, none of which a smart contract can do. Almost every first crypto purchase happens on one.

The point people miss is that a balance on a centralized exchange is a claim against a company, not coins you hold. The exchange records that it owes you 0.1 BTC. Whether it can pay depends on its solvency, which is a different question from whether Bitcoin works.

How it works

You open an account, pass identity checks, and deposit fiat by bank transfer or card. The exchange credits your account in its own internal ledger.

Trades then happen inside that ledger. When you buy from another customer, no blockchain transaction occurs at all: the exchange simply decrements one internal balance and increments another. This is why trades settle instantly and why an exchange can offer sub-cent price increments that would be uneconomic on chain.

The blockchain is involved only at the edges. Deposits of crypto arrive on chain and are credited after a set number of confirmations. Withdrawals are real transactions, and the exchange charges a withdrawal fee that is often higher than the network cost.

The exchange holds the keys throughout. Most keep the bulk of assets in cold storage and a working float in hot wallets to service withdrawals.

Example

Illustrative arithmetic. You deposit 500 dollars by bank transfer at no deposit fee and place a market buy. The venue charges a 0.40 percent taker fee, so 2 dollars goes to the exchange and 498 dollars buys crypto. If the quoted spread is 5 basis points, you give up another 25 cents crossing it. Withdrawing to your own wallet later costs a flat network fee set by the exchange, which does not scale with the amount, so withdrawing 500 dollars costs the same as withdrawing 5,000.

Why it matters when you buy

The choice of venue sets almost everything about a purchase: whether you can open an account at all where you live, what payment methods you can use, what the trade costs, and which assets are listed. The fee comparison shows the cost side, the exchange pages show availability and licensing, and the buyability grades show how easy each coin is to obtain.

dex — the non-custodial contrast; custodial — who holds the keys; counterparty risk — what you take on by leaving funds there; proof of reserves — a partial check on solvency; maker taker fee — why resting orders pay less.

Questions

Is a centralized exchange safe?

It removes the risk of you losing your own keys and adds the risk of the company failing or freezing withdrawals. Which trade you prefer depends on the amount and how long you intend to hold it, and the two risks are not comparable in kind.

Do I need to withdraw my coins?

Not for the exchange to work. Withdrawing moves you from a claim on a company to assets you control directly, which removes counterparty risk and adds full responsibility for your own backups.

Why is a trade instant but a withdrawal slow?

Trades are internal ledger entries. Withdrawals are real blockchain transactions that must be broadcast and confirmed, and many exchanges batch them or review them for security before sending.

Guides that use this term

  • How Crypto Exchanges Make Money

    A crypto exchange earns most of its money from trading fees charged on both sides of every trade, and adds revenue from the spread built into simple buy buttons, deposit and withdrawal charges, listing arrangements, interest on customer balances, and paid products such as staking and derivatives.

  • Self-Custody vs Exchange Custody: How to Decide

    Deciding between self-custody and exchange custody means choosing which failure you would rather be exposed to, a company that loses or freezes your assets or a mistake of your own that nobody can undo, and most people resolve it by splitting holdings rather than picking one for everything.

  • Where Stablecoin Yield Comes From, and What Can Go Wrong

    Stablecoin yield is paid by borrowers who want leverage, by issuers sharing the interest earned on their reserves, or by trading strategies, so the rate you are quoted is compensation for credit, contract, and platform risk rather than interest on a deposit.

  • How to Verify a Token Contract Address Before You Buy

    A token's contract address is its only real identity, so verifying one means getting the address from the project's own official channel, confirming the same address independently from a second source, and checking on a block explorer that the contract is what it claims to be before you trade against it.

  • Centralized vs Decentralized Exchanges: Which Should You Use

    A centralized exchange holds your coins and your identity documents but lets you buy with a bank transfer or card, while a decentralized exchange requires no account and never takes custody but can only swap crypto you already own, so most people start on the first and use the second for assets it does not list.