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Alternative Mempools

We strongly recommend you follow the public mempool validation rules in ERC-7562, but if you believe an alternative mempool is required for your application please contact us at [email protected].

Your application will be more robust if it uses the public ERC-4337 mempool. It allows you to work with any ERC-4337 bundler, paymaster, or account and prevents lock in to a single provider. It also guarantees that you will get the best price for your user operations because they can be picked up by more bundlers.

The tradeoff is that using this mempool imposes some restrictions on what user operations can do. This prevents denial-of-service attacks on the mempool. These rules can be intimidating, but in most practical applications you won't approach them.

ERC-7562 contains the full set of validation rules for the canonical public ERC-4337 mempool.

Guiding Principles

A public mempool of valid UserOperations is susceptible to denial-of-service attacks unless some access to the EVM is restricted during the validation phase.

The rules in ERC-7562 are enforced by bundlers. The codes that you may encounter are:

• General Reputation Rules (GREP prefix)
• Opcode Rules (OP prefix)
• Code Rules (COD prefix)
• Storage Rules (STO prefix)
• Staked Entities Reputation Rules (SREP prefix)
• Entity Specific Rules (EREP prefix)
• Unstaked Paymasters Reputation Rules (UREP prefix)

Staking Rules

Some types of ERC-4337 entities can have enhanced permissions with the public mempool if they stake with the EntryPoint. Here are the common values required.