What Is DEX? Beginner Guide to Decentralized Exchanges (Part 1)
mscode075 min read·Just now--
If you’ve spent time in Web3, you’ve probably heard the term DEX.
DEX stands for Decentralized Exchange — one of the most important innovations in crypto.
Instead of trusting a company to hold your funds and process trades, a DEX allows users to trade directly through blockchain-based smart contracts.
In this guide, we’ll break it down in simple words.
What is DEX?
A DEX (Decentralized Exchange) is a platform where users swap cryptocurrencies without relying on a central company.
Unlike traditional exchanges, you usually keep control of your wallet and funds.
Popular examples include:
- Uniswap
- Orca
- Meteora
- Raydium
How Does a DEX Work?
When you connect wallets like Phantom or MetaMask, you can swap one token for another.
Example:
Swap:
1 SOL → USDC
The DEX smart contract processes the trade using available liquidity.
You remain in control of your wallet until you approve the transaction.
What is a DEX aggregator?
A DEX aggregator compares prices across multiple exchanges and finds the best route for your swap.
Instead of checking each platform manually, it does it instantly.
Simple example
1 SOL → USDC
- Orca: 84.90 USDC
- Raydium: 85.10 USDC
- Meteora: 85.05 USDC
The aggregator may route you through Raydium for the best value.
Popular examples:
- Jupiter
- 1inch
How Decentralized Exchange works
As we click the swap button on a wallet like Phantom / MetaMask, we will get the swapping screen.
Here we can see the swapping screen, where we can add which token we want to swap and In which quantity we want to swap. After that, we’ll get the full price, and we’ll get what the platform fee is. There are many other terms here in the image below, such as Slippage, which is one of the most importent thing to know, as it directly impact your amount you’ll get in the bank.
What is Slippage?
Slippage is the difference between the price you expected and the final price you received.
This happens because:
- Market moves quickly
- Liquidity is low
- Large orders impact price
Example:
You expect 100 USDC for your token.
But during execution, you receive 98 USDC.
That 2% difference is slippage.
Why It Matters
If your slippage tolerance is too low:
- The transaction may fail
If too high:
- You may receive a worse price
So always be careful, especially on volatile or low-liquidity tokens.
DEX vs CEX: What’s the Difference?
What Is a CEX?
CEX means Centralized Exchange.
Examples:
- Binance
- CoinDCX
- Coinbase
These platforms are run by companies.
You create an account, complete verification, and trade inside their system.
What is the difference between Dex and Cex?
Cex jargoes
Order Book: An order book is a digital list of buy and sell orders placed by traders for a particular asset, such as cryptocurrencies.
An order book is a real-time list of all current buy and sell orders for a particular asset, such as stocks, commodities, or cryptocurrencies. It provides a snapshot of what buyers are willing to pay (bids) and what sellers are asking for (asks), helping traders gauge market supply and demand. Order books are a standard tool on centralized exchanges.
How Order Books Work
In high-liquidity markets, order books are live and constantly being updated. As new buy or sell orders come in, they are added to the list. When a trade happens, the relevant orders are removed from the order book. Essentially, order books show the open orders that represent ongoing negotiations between buyers and sellers.
If you’re a buyer, your order will be added based on the maximum price you’re willing to pay. If you’re a seller, it’s based on the minimum price you’re willing to accept.
Key Components of an Order Book
- Buy orders (bids): These show what buyers are ready to pay. Usually, they’re listed from the highest to the lowest bid price.
- Sell orders (asks): These show what sellers want to get for their assets. They’re listed from the lowest to the highest ask price.
- Price and quantity: For each order, the book shows how much the trader wants to buy or sell and at what price.
- Spread: This is the gap between the highest bid and the lowest ask, also called the bid-ask spread. A smaller spread generally indicates a more liquid market.
- Order matching: When a buy and sell order line up, the matching engine executes the trade. If a buyer agrees to pay the seller’s asking price, or a seller agrees to accept a bid, the trade goes through.
Part 2 Coming Soon
In Part 2, I’ll cover:
- Liquidity pools
- AMMs
- LP rewards
- Risks in DEX trading
- MEV & sandwich attacks
✨ Thanks for reading! If you would like more Solana tech blogs, subscribe to me here for weekly insights.
About Me
I’m Abhishek (mscode07) — developer & indie hacker.
I write about Web3, building, and learning in public.
Feedback
I’m still improving my writing —
So feel free to share honest feedback (good or bad).
