How Do Decentralized Exchanges (DEXs) Mitigate Reentrancy Risks in Their Swap Functions?

DEXs, particularly those using Automated Market Maker (AMM) models, mitigate reentrancy by ensuring all internal state updates (token balances, pool reserves) are completed before any external token transfer is initiated. This adheres strictly to the Checks-Effects-Interactions pattern.

Additionally, many modern DEXs use non-reentrant function modifiers to explicitly lock the function during execution, preventing external calls from re-entering the swap logic.