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Introducing ERC-4337: Account Abstraction Using Alt Mempool for Enhanced Decentralization and Flexibility

· 3 min read
Mike Thrift

Hello and welcome back to our blockchain blog! Today, we will be diving into an exciting new proposal called ERC-4337, which introduces account abstraction to Ethereum without requiring any consensus-layer protocol changes. Instead, this proposal relies on higher-layer infrastructure to achieve its goals. Let's explore what ERC-4337 has to offer and how it addresses the limitations of the current Ethereum ecosystem.

What is ERC-4337?

ERC-4337 is a proposal that introduces account abstraction to Ethereum through the use of a separate mempool and a new type of pseudo-transaction object called a UserOperation. Users send UserOperation objects into the alternative mempool, where a special class of actors called bundlers package them into a transaction making a handleOps call to a dedicated contract. These transactions are then included in a block.

The proposal aims to achieve several goals:

  1. Enable users to use smart contract wallets with arbitrary verification logic as their primary accounts.
  2. Completely remove the need for users to have externally owned accounts (EOAs).
  3. Ensure decentralization by allowing any bundler to participate in the process of including account-abstracted user operations.
  4. Enable all activity to happen over a public mempool, eliminating the need for users to know direct communication addresses of specific actors.
  5. Avoid trust assumptions on bundlers.
  6. Avoid requiring any Ethereum consensus changes for faster adoption.
  7. Support other use cases such as privacy-preserving applications, atomic multi-operations, paying transaction fees with ERC-20 tokens, and developer-sponsored transactions.

Backwards Compatibility

Since ERC-4337 does not change the consensus layer, there are no direct backwards compatibility issues for Ethereum. However, pre-ERC-4337 accounts are not easily compatible with the new system because they lack the necessary validateUserOp function. This can be addressed by creating an ERC-4337 compatible account that re-implements the verification logic as a wrapper and setting it as the original account’s trusted op submitter.

Reference Implementation

For those interested in diving deeper into the technical details of ERC-4337, a reference implementation is available at

Security Considerations

The entry point contract for ERC-4337 must be heavily audited and formally verified, as it serves as a central trust point for the entire system. While this approach reduces the auditing and formal verification load for individual accounts, it does concentrate security risk in the entry point contract, which must be robustly verified.

Verification should cover two primary claims:

  1. Safety against arbitrary hijacking: The entry point only calls an account generically if validateUserOp to that specific account has passed.
  2. Safety against fee draining: If the entry point calls validateUserOp and passes, it must also make the generic call with calldata equal to op.calldata.


ERC-4337 is an exciting proposal that aims to introduce account abstraction to Ethereum without requiring consensus-layer protocol changes. By using higher-layer infrastructure, it opens up new possibilities for decentralization, flexibility, and various use cases. While there are security considerations to address, this proposal has the potential to greatly improve the Ethereum ecosystem and user experience.