MetaMask Connect is a complete rewrite of the legacy `@metamask/sdk`. It introduces asynchronous initialization with `createEVMClient`, a singleton client pattern, built-in multichain support for both EVM and Solana, CAIP-25 session management, and improved relay server infrastructure.
- [Introduction]( MetaMask Connect - Dapp Wallet Integration SDK | MetaMask developer documentation )
- [Migration guide (step-by-step upgrade)](Migrate from Legacy SDK to MetaMask Connect EVM | MetaMask developer documentation)