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ERC-4337

Overview and breakdown of the core Account Abstraction standard using the alt mempool approach.

ERC-4337 is the foundational standard for Account Abstraction (AA) on Ethereum. It enables programmable, secure, and flexible smart wallets—without requiring any changes to the Ethereum consensus layer.

🚀 What Does It Enable?

  • Programmable smart wallets with custom auth (e.g., multisig, passkeys)
  • Gas abstraction using ERC-20 tokens or Paymasters
  • Account deployment on first use via initCode
  • Bundled operations for better UX and gas efficiency
  • Signature flexibility, enabling recovery, guardians, and more

🧱 Key Components

🧾 UserOperation

A new object type representing user intent. Think of it as a structured meta-transaction.

interface UserOperation {
  sender: address;
  nonce: uint256;
  initCode: bytes;
  callData: bytes;
  callGasLimit: uint256;
  verificationGasLimit: uint256;
  preVerificationGas: uint256;
  maxFeePerGas: uint256;
  maxPriorityFeePerGas: uint256;
  paymasterAndData: bytes;
  signature: bytes;
}

This structure is propagated through a separate UserOp mempool, not the legacy Ethereum transaction pool.

🚦 EntryPoint Contract

The singleton router that:

  • Calls validateUserOp() on the sender account
  • If present, calls validatePaymasterUserOp() on the Paymaster
  • Executes the callData if validation succeeds
  • Holds deposits for accounts, and deposits + stakes for paymasters

Smart accounts must explicitly trust a specific EntryPoint contract. During validation, wallets check msg.sender == EntryPoint to ensure the operation is invoked through the correct entrypoint.

📦 Bundlers

Nodes that:

  • Monitor the UserOp mempool
  • Select and simulate valid UserOperations
  • Submit bundles as part of blocks they build onchain

Bundlers assume the gas cost risk and are reimbursed by user accounts or Paymasters. They may apply local policies or reputation scoring (e.g., ERC-7562).

💰 Paymasters

Optional contracts that:

  • Sponsor gas for accounts under programmable conditions
  • Must stake and deposit ETH into the EntryPoint
  • Can enforce rules off-chain or on-chain (e.g., API-based validation)

If validatePaymasterUserOp() succeeds, the Paymaster covers execution costs. If the operation fails, the Paymaster still pays the network fees.

🔎 Validation Flow

  1. User sends UserOperation to a bundler
  2. Bundler simulates validation using EntryPoint’s simulateValidation()
  3. Checks signature, nonce, balance/stake, and paymaster logic
  4. If valid, the bundler includes it in a bundle
  5. Bundle is sent via handleOps(), and UserOperations are executed atomically

🔐 Security & DoS Protections

  • EntryPoint reverts with FailedOp if validation or execution fails
  • Bundlers must pre-simulate using debug_traceCall to avoid gas loss
  • ERC-7562 defines additional validation rules (e.g., no storage writes in validateUserOp)
  • Only staked entities can access shared state during validation

🔄 Integration with Other Standards

  • EIP-7702 — Temporary delegation of EOAs to smart logic
  • ERC-6900 / 7579 — Modular account plugin standards
  • ERC-6492 — Signature validation for undeployed wallets
  • RIP-7560 — Native transaction type proposal for protocol-layer AA

📚 Further Reading

🤖 Example Use Cases

  • Gasless onboarding with verifying Paymasters
  • Multisig wallets using passkeys and guardian recovery
  • Games batching actions and sponsoring players
  • DAOs managing on-chain workflows and access control

✅ Summary

ERC-4337 is the backbone of smart wallet infrastructure on Ethereum. It introduces a new validation-execution flow via EntryPoint and enables bundlers, Paymasters, and flexible signatures—without requiring changes to Ethereum’s base protocol or compromising on decentralization or censorship resistance.