What is the Account Abstraction (ERC-4337) proposal?

Account Abstraction (ERC-4337) transforms Ethereum's user accounts from simple key-controlled Externally Owned Accounts (EOAs) into programmable smart contract wallets, unlocking radically improved UX without L1 protocol changes. Problems with EOAs: you must have ETH to pay gas (friction for new users), losing a private key means losing all funds (no recovery), every dApp requires a signature (poor UX). ERC-4337 introduces: (1) UserOperation — a pseudo-transaction object representing a user's intent, signed by any signing scheme the wallet supports; (2) Bundler — nodes that collect UserOperations and include them in real transactions; (3) EntryPoint contract — the global singleton that processes UserOperations; (4) Paymaster — sponsors gas fees for users; enables gasless transactions (sponsored by dApps) or paying gas in ERC-20 tokens. Benefits: (1) Social recovery — recover wallet via trusted guardians if private key is lost; (2) Multi-sig — require multiple signatures for high-value transactions; (3) Batch transactions — approve + swap in one user action; (4) Gasless UX — dApps pay gas; (5) Session keys — temporary keys for games. ERC-4337 is deployed on mainnet and all major L2s; wallets: Alchemy's Light Account, Biconomy, Safe (ex-Gnosis Safe).