What is ERC-4337?
ERC-4337 is the Ethereum standard for account abstraction that enables smart contract wallets with programmable transaction validation, gas sponsorship, and batched operations — without requiring protocol-level changes to Ethereum.
WHY IT MATTERS
ERC-4337 introduces a parallel transaction pipeline for smart accounts. Instead of regular transactions, smart accounts submit UserOperations to a mempool. Bundlers pick up these UserOperations, validate them against the account's rules, and submit them to the EntryPoint contract for on-chain execution.
Key innovations include: Paymasters (third parties can pay gas on behalf of users/agents), batched operations (multiple actions in one transaction), and custom validation (any signing scheme or authorization logic). This makes wallets programmable in ways EOAs never could be.
For agent developers, ERC-4337 enables: session keys (temporary, scoped agent authority), spending limits (on-chain enforcement of budgets), sponsored gas (agents don't need ETH for gas), and modular extensions (add new capabilities to existing wallets).
HOW POLICYLAYER USES THIS
PolicyLayer works with ERC-4337 smart accounts to validate UserOperations against spending policies. Agent transactions pass through PolicyLayer's policy checks as part of the UserOperation validation flow — enforcing rules at the smart account level.