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What Is Decentralised Exchange (DEX)? Meaning & Example

A plain-English definition of Decentralised Exchange (DEX): what it means, how it works, and a simple example.

Quick answer

A decentralised exchange (DEX) is a peer-to-peer crypto trading platform that uses smart contracts instead of a central authority to match and settle trades.

A decentralised exchange, or DEX, is a cryptocurrency trading platform that operates without a central company managing order books, holding funds or requiring user accounts. Instead, trades are executed by smart contracts on a blockchain, and users trade directly from their own crypto wallets.

How a DEX works

Most modern DEXs use an automated market maker (AMM) model. Instead of matching buyers with sellers through an order book, an AMM uses liquidity pools, collections of tokens locked in smart contracts by liquidity providers.

When you trade on a DEX like Uniswap, you are swapping tokens with a pool rather than with another person. The pool's smart contract uses a mathematical formula to determine the exchange rate based on the ratio of tokens in the pool.

DEX vs centralised exchange

FeatureDEXCentralised exchange
Custody of fundsYou hold your keysExchange holds your funds
KYC requiredUsually noYes, in India
Available tokensAny token on the blockchainCurated list
Trading speedDepends on blockchainUsually faster
Customer supportNoneAvailable
RegulationLargely unregulatedRegulated in most jurisdictions

Popular DEXs

  • Uniswap: the largest DEX on Ethereum.
  • PancakeSwap: runs on BNB Chain with lower fees.
  • SushiSwap: multi-chain DEX with additional DeFi features.
  • Jupiter: leading DEX aggregator on Solana.

DEXs and India

Indian users can access DEXs using a non-custodial wallet like MetaMask. No Indian exchange directly integrates with DEXs, so users typically buy crypto on a centralised Indian exchange, transfer to a personal wallet, and then use a DEX. All gains from DEX trading are taxable at 30% under Section 115BBH.

Risks

  • Smart contract risk: a bug in the DEX's code can result in loss of funds.
  • Impermanent loss: liquidity providers can lose value compared to simply holding the tokens.
  • Front-running: bots can detect your pending transaction and trade ahead of you to profit at your expense.
  • Fake tokens: anyone can create a token on a DEX, so scam tokens are common. Always verify contract addresses.
  • No recourse: there is no customer support or undo button if something goes wrong.

Decentralised Exchange (DEX) FAQs

The questions people most often ask about Decentralised Exchange (DEX), answered for Indian readers.

Are decentralised exchanges legal in India?

There is no specific law banning DEX usage in India. Indian users can interact with DEXs through their own crypto wallets. However, gains from DEX trading are treated as VDA income and taxed at 30%. The 1% TDS applies only on Indian exchange transactions, not directly on DEX trades.

Do I need KYC to use a DEX?

Most DEXs do not require KYC because they are smart contract-based protocols, not registered companies. You only need a crypto wallet. However, the on-ramp from INR to crypto through an Indian exchange does require KYC, and blockchain transactions are publicly traceable.

What is an automated market maker?

An automated market maker is the mechanism most DEXs use to set token prices. Instead of matching buy and sell orders, it uses a liquidity pool and a mathematical formula. The price adjusts automatically based on the ratio of tokens in the pool as trades change the balance.

How do I report DEX trades for Indian tax?

You must track and report all DEX trading profits as VDA gains in your income tax return, taxed at 30% under Section 115BBH. Since DEXs do not issue tax certificates, maintaining your own records of every trade, including dates, amounts and wallet addresses, is essential.

What is the difference between a DEX and an exchange like WazirX?

WazirX is a centralised exchange that holds your funds, requires KYC and offers customer support. A DEX is a smart contract protocol where you trade from your own wallet without creating an account. DEXs offer more token variety but less convenience and no customer support.

Related terms

Smart ContractLiquidity PoolDeFi (Decentralised Finance)Crypto WalletCryptocurrencyEthereum

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A note on accuracy: this definition is for general education, not personalised financial or tax advice. Figures are illustrative and rules can change. Confirm anything that affects a real decision.