A decentralized exchange lets you trade crypto without handing your funds to a company. You connect a wallet, swap one token for another, and the trade settles on-chain. There is no account, no KYC, and no withdrawal request. Uniswap, SushiSwap, and Curve are the major ones. Most use automated market makers instead of order books. You trade against a liquidity pool, and the price comes from a formula.

The benefits are control and access. Your keys stay in your wallet until you sign the swap. Nobody can freeze your account or block your region. The trade-offs are real. Gas fees on Ethereum can exceed the value of a small trade. Slippage can eat into your return. Impermanent loss affects liquidity providers. Smart contract bugs can drain pools. DEXs remove the middleman but replace that trust with code risk.

DEX characteristics

• Non-custodial — you keep your keys
• Permissionless — anyone can list a token
• On-chain — every trade is a blockchain transaction
• AMM-based — most use liquidity pools, not order books

DEX volumes have grown but still trail centralized exchanges. The gap is closing as layer 2 networks reduce fees and improve speed.