Smart Contracts
User Operation
An abstracted transaction request used in account abstraction, processed by a mempool and bundlers.
Last Updated
2026-03-29
Related Concepts
What is User Operation?
A User Operation (UserOp) is an abstracted transaction request standardized by EIP-4337. Instead of a rigid transaction format, it is a flexible instruction sent to a dedicated mempool where bundlers collect and batch it onto the blockchain.
How does User Operation work?
- A user creates a UserOp specifying their smart account, calldata, and gas limits.
- The UserOp is broadcast to the EIP-4337 mempool.
- A bundler collects multiple UserOps and wraps them into a single on-chain transaction.
- The EntryPoint contract validates and executes each UserOp against its smart account.
Why does User Operation matter?
It enables smart contract wallets to function like regular accounts without changing Ethereum's core protocol unlocking gas sponsorship, batched transactions, and social recovery.
Key features of User Operation
- Flexible format compared to rigid traditional transactions
- Processed by independent bundlers, not miners directly
- Enables paymasters to sponsor gas in any token
- Standardized under EIP-4337 for cross-platform compatibility
Examples of User Operation
A user pays gas in USDC instead of ETH by creating a UserOp with a paymaster. A bundler batches 50 UserOps into one transaction, reducing per-user costs significantly.