ERC-4337 describes account abstraction using user operations that bundlers submit through an EntryPoint contract. A user operation contains instructions and validation information for a smart account rather than being identical to a conventional externally owned account transaction. The account's logic determines whether the operation is authorized. This permits application-defined authentication and account behavior within the framework, while bundlers and the EntryPoint organize validation, execution, and compensation for the resources consumed.

Imagine a new user creating a smart account and making an application interaction without first acquiring the network's native token. A paymaster can agree to sponsor the operation according to its own policy, and a bundler submits the encompassing transaction. Someone still pays the network fee; sponsorship changes who bears it and under what conditions. An application should identify the sponsor, eligibility conditions, and possible fallback behavior rather than advertising the interaction as if blockchain execution no longer has a cost.

Support depends on compatible account contracts, EntryPoint versions, bundlers, and optional paymasters. A recovery feature or spending limit exists only if the chosen account implementation actually enforces it. A sponsor can also decline an operation, and a bundler's simulation is not a guarantee of later success under changed state. Related proposals such as EIP-7702 provide different account capabilities and should not be conflated with ERC-4337 itself. Evaluate the deployed account's authorization and upgrade paths, not merely the interface label shown by the wallet.