What Is a DEX (Decentralized Exchange)? How It Works, DEX vs CEX & How to Use One

A DEX (Decentralized Exchange) is a decentralized exchange that uses smart contracts on a blockchain to let users trade cryptocurrencies directly with each other — without a central intermediary. The key advantage is that you never need to deposit assets into an exchange; instead, you trade directly from your own wallet. This article explains how DEXs work, how they differ from CEXs, and how to use them, all in beginner-friendly terms.

What you'll learn in this article

• How DEXs work and the difference between AMM and order book models
• How DEXs compare to CEXs (centralized exchanges) and when to use each
• A comparison of top DEXs: Uniswap, Jupiter, Raydium, and dYdX
• How to use a DEX step by step, plus risk management tips

DEX stands for "Decentralized Exchange." Unlike traditional exchanges (CEXs), where a company processes orders, a DEX uses smart contracts (self-executing programs) on a blockchain to handle trades.

3 Key Features of DEXs

DEXs have three important characteristics:

• Self-custody of assets: You don't need to deposit tokens into an exchange — you trade directly from your wallet. This eliminates exchange risk, such as the FTX collapse in 2022
• 24/7 trading: Since smart contracts process trades automatically, there's no downtime for maintenance. You can trade anytime, from anywhere in the world
• Wide token selection: While CEXs require listing approval, DEXs allow tokens to be traded without a screening process. Uniswap offers over 1,500 tradable tokens (as of March 2026)

DEX Market Size

DEX trading volume has been growing year after year. As of January 2026, Uniswap's 30-day trading volume reached approximately $47 billion. Jupiter and Raydium on the Solana chain together account for about 50% of total DEX volume, with Ethereum-based and Solana-based DEXs leading the market as two dominant forces.

The total TVL (Total Value Locked) across the entire DeFi ecosystem exceeds $100 billion, and DEXs have grown into a core pillar of this ecosystem.

DEXs use two main trading mechanisms: AMM and order book. Understanding how each works will help you choose the right DEX for your needs.

AMM (Automated Market Maker)

AMM (Automated Market Maker) is the most widely used DEX trading model today. Instead of matching buyers and sellers like a traditional exchange, it executes trades using token reserves called "liquidity pools."

Here's how AMM works:

1. LPs (Liquidity Providers) deposit token pairs (e.g., ETH and USDC) into a pool
2. The exchange rate is automatically determined by a mathematical formula based on the token ratio in the pool
3. Each trade changes the ratio in the pool, automatically adjusting the price
4. LPs earn a share of the trading fees as rewards

Leading AMM DEXs include Uniswap (Ethereum), Raydium (Solana), and PancakeSwap (BNB Chain).

Order Book Model

The order book model works like a CEX, listing buy and sell orders on a book and matching them. It supports advanced order types such as limit orders and stop-loss orders.

dYdX is the leading order book DEX, supporting up to 20x leverage trading. It runs on its own chain (built on Cosmos SDK), and its processing speed rivals that of CEXs.

AMM vs Order Book Comparison

DEXs and CEXs (Centralized Exchanges) each have distinct strengths. It's not about which is better — it's about choosing the right tool for the job.

DEXs are ideal for: Users who want self-custody, those trading altcoins not listed on CEXs, privacy-conscious traders, and active DeFi participants

CEXs are ideal for: Crypto beginners, those wanting to buy directly with Japanese yen, users who need customer support, and those requiring fast trade execution

Here's a comparison of four of the most popular DEXs as of 2026. Since supported chains and gas fees vary significantly, it's important to choose one that matches your trading needs.

Uniswap

Uniswap launched on Ethereum in 2018 as a pioneer of the AMM model. Its TVL ranks among the highest of all DEXs, with a 30-day trading volume of approximately $47 billion as of January 2026. It supports over 10 chains, including Ethereum, Base, Polygon, and Arbitrum. UNI governance token holders can vote on protocol upgrades.

Jupiter

Jupiter is a DEX aggregator on the Solana chain. Rather than being a standalone DEX, it searches across multiple DEXs — including Orca, Raydium, and Meteora — to find the best price for users. It's widely used as the go-to choice for swapping tokens on Solana and also offers limit orders and DCA (Dollar-Cost Averaging) features.

Raydium

Raydium is an AMM DEX built on the Solana blockchain. Leveraging Solana's high-performance infrastructure, it delivers near-instant transaction confirmation and extremely low fees of just a few cents per trade. It also features a launchpool for new tokens and is widely used for trading meme coins.

dYdX

dYdX is a DEX specializing in derivatives trading. It offers perpetual futures trading with up to 20x leverage. Running on its own chain (built on Cosmos SDK), it can process over 10,000 transactions per second, delivering a trading experience that rivals CEXs.

Here's a step-by-step guide to swapping tokens on a DEX. We'll use an AMM DEX (like Uniswap) as an example.

Step 1: Set Up Your Wallet

You need a Web3 wallet to use a DEX. MetaMask is the standard choice for Ethereum-based DEXs, and Phantom for Solana-based ones.

1. Install the wallet app (browser extension or smartphone app)
2. Safely store your seed phrase (a 12–24 word recovery phrase) — writing it down on paper is recommended
3. Add the blockchain network you plan to use
4. Deposit the base currency for gas fees (such as ETH or SOL) into your wallet

Step 2: Connect Your Wallet to the DEX

1. Visit the official website of the DEX you want to use
2. Click the "Connect Wallet" button in the top right corner
3. Select your wallet (e.g., MetaMask) and approve the connection

⚠️ Always verify you're on the official URL. Fake sites mimicking popular DEXs frequently appear in search ads and social media. Accessing via bookmarks is the safest approach.

Step 3: Swap Tokens

1. Select the token you want to swap from and the token you want to receive
2. Enter the amount you want to exchange
3. Review the displayed rate, fees, and slippage (price deviation tolerance)
4. Click "Swap" and approve the transaction in your wallet
5. Wait for the transaction to be processed on the blockchain (a few seconds on Solana, tens of seconds to a few minutes on Ethereum)

Step 4: Record Your Transaction History

Unlike CEXs, DEXs don't offer CSV export for trade history, so you need to keep your own records for tax purposes. You can check transaction history using blockchain explorers like Etherscan (Ethereum) or Solscan (Solana). Under Japanese tax law, cryptocurrency trading profits must be reported as miscellaneous income.

To use DEXs safely, it's important to understand these five risks. By knowing the risks and taking proper precautions, you can use DEXs with confidence.

Slippage

Slippage is the difference between the price at the time you place your order and the actual execution price. Tokens with low trading volume (low liquidity) tend to have higher slippage. Set your slippage tolerance (typically 0.5%–1%) in the DEX settings.

Impermanent Loss

When you deposit tokens in a liquidity pool, if the price ratio changes between deposit and withdrawal, your assets may be worth less than if you had simply held them. Choosing stablecoin pairs (such as USDT/USDC) can help reduce this risk.

Smart Contract Vulnerabilities

If a DEX's smart contracts contain bugs or design flaws, funds could be lost. Choose DEXs that have undergone multiple security audits. Major DEXs like Uniswap have been reviewed by multiple auditing firms.

Phishing Scams and Fake Sites

Scammers create websites that closely resemble official DEX sites. If you connect your wallet to a fake site, your assets can be stolen. Always access DEXs from bookmarks or verified links from official social media accounts.

Token Approval Risks

When swapping tokens on a DEX, you're asked to "Approve" — granting the smart contract permission to move your tokens. Unlimited approvals can leave your assets vulnerable to malicious contracts. Only approve the amount you need, and revoke approvals for DEXs you're no longer using with tools like Revoke.cash.

⚠️ Using DEXs involves smart contract risks and phishing risks. Start with small amounts and make sure you fully understand the risks before proceeding.

Q. Do I need KYC (identity verification) to use a DEX?

Most DEXs don't require identity verification — you can start trading just by connecting your wallet. However, under Japanese tax law, profits from cryptocurrency trades are subject to tax filing. Since DEXs don't manage your transaction history for you, it's recommended to keep records of each trade.

Q. How much are DEX trading fees?

DEX fees consist of two components: "swap fees" and "gas fees." Swap fees vary by DEX — Uniswap typically charges 0.3%. Gas fees fluctuate based on blockchain congestion, ranging from a few hundred to several thousand yen on Ethereum, and just a few yen on Solana.

Q. Can I buy crypto directly with Japanese yen on a DEX?

DEXs cannot handle fiat currencies (like Japanese yen) directly. The typical flow is: first exchange yen for crypto on a CEX (domestic exchange) like OKJ (OKCoinJapan), transfer it to your wallet, then use the DEX. Buying ETH or SOL on OKJ is the standard starting point.

Q. How are DEX trades taxed in Japan?

Under Japanese tax law, token swaps on DEXs are treated as crypto-to-crypto exchanges and are taxable events. If a profit is realized at the time of the swap, it must be reported as miscellaneous income. If your annual income from crypto trading exceeds ¥200,000, you are required to file a tax return. Tax calculation tools like Koinly or cryptact can be helpful.

Q. Which DEX is best for beginners?

For trading Ethereum-based tokens, Uniswap is recommended. For Solana-based tokens, Jupiter is the best choice. Both have user-friendly interfaces, deep liquidity, and strong security. We recommend starting with a small amount (around a few thousand yen).

To use a DEX, you first need to purchase cryptocurrencies like ETH or SOL on a domestic exchange. With OKJ (OKCoinJapan), you can easily buy ETH and SOL with Japanese yen and send them directly to your wallet to start using DEXs.

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A DEX (Decentralized Exchange) is a smart contract-powered exchange where you can trade crypto while maintaining self-custody of your assets. Compared to CEXs, DEXs offer wider token selection and greater privacy, but come with more complexity and no customer support.

Choosing the right DEX for your needs is key: Uniswap (Ethereum), Jupiter and Raydium (Solana), or dYdX (derivatives). Safe usage requires proper risk management, including slippage settings and phishing protection.

Related guides: What Is DeFi | What Is a DAO | What Are NFTs | What Is Solana | What Is Staking | What Are Altcoins | What Are Meme Coins | What Is Web3 | What Is DePIN | What Is Ripple

References:

• Uniswap Official Documentation
• DeFi Llama — DEX Volume Data
• FSA Japan — Cryptocurrency Warnings