Glossary
UserOperation
A pseudo-transaction signed by an ERC-4337 smart-contract wallet — sent to a separate mempool, packaged by a bundler, and executed via the EntryPoint contract.
A UserOperation (UserOp) is the unit of activity in ERC-4337 account abstraction. It looks like a transaction — sender, nonce, calldata, gas limits — but it is signed by the smart-contract wallet, sits in a separate mempool, and is settled via the EntryPoint rather than directly on Ethereum's normal mempool.
The shape lets each smart wallet define its own validation logic (signature scheme, nonce, gas payment), which is how account abstraction supports passkeys, multisig signers, social recovery, and stablecoin gas payment without a protocol change.