Account Abstraction (ERC-4337 / ERC-7579)

ERC-4337 replaces externally-owned account (EOA) transactions with UserOperations — signed intents processed by a Bundler and executed through an on-chain EntryPoint contract. This enables smart contract wallets with features impossible with EOAs: batched calls, gas sponsorship, social recovery, session keys, and modular validation logic.

Nethereum provides a complete ERC-4337 stack: client libraries for building and sending UserOperations, an in-process bundler with mempool and reputation, typed contract services that route through AA automatically, and ERC-7579 modular account support.

Architecture

User signs UserOperation
        |
        v
   Bundler (JSON-RPC)
        |
        v
   EntryPoint.handleOps()
        |
        +--> SmartAccount.validateUserOp()
        |         |
        |         +--> (optional) Paymaster.validatePaymasterUserOp()
        |
        +--> SmartAccount.execute(callData)

The Bundler collects UserOperations from users, validates them, estimates gas, and submits them to the EntryPoint contract in a batch transaction. The EntryPoint verifies each operation's signature via the smart account's validation logic, optionally checks a Paymaster for gas sponsorship, then executes the call.

The Simple Path

Most developers don't need to build UserOperations manually. Nethereum's AAContractHandler lets you switch any existing typed contract service to route through Account Abstraction automatically:

using Nethereum.AccountAbstraction;

// Any existing contract service — ERC-20, ERC-721, or your own
var erc20Service = web3.Eth.ERC20.GetContractService(tokenAddress);

// One line: switch to AA. All future calls become UserOperations.
erc20Service.ChangeContractHandlerToAA(
    accountAddress, privateKey, bundlerUrl, entryPointAddress);

// Use the service exactly as before — AA is transparent
var receipt = await erc20Service.TransferRequestAndWaitForReceiptAsync(
    new TransferFunction { To = recipient, Value = amount });

Gas estimation, nonce management, signing, and bundler submission are all handled automatically.

Key Concepts

Concept	Description
UserOperation	A signed intent describing what a smart account should execute. Replaces traditional transactions.
Smart Account	A contract wallet that validates and executes UserOperations. Supports custom validation logic.
Bundler	An off-chain service that collects UserOperations and submits them to the EntryPoint.
EntryPoint	The singleton on-chain contract that coordinates validation and execution of UserOperations.
Paymaster	An optional contract that sponsors gas for UserOperations, enabling gasless transactions.
Factory	A contract that deploys new smart accounts via CREATE2 for deterministic addresses.

EntryPoint Versions

Version	Address	Notes
V06	0x5FF137D4b0FDCD49DcA30c7CF57E578a026d2789	Original ERC-4337
V07	0x0000000071727De22E5E9d8BAf0edAc6f37da032	Packed UserOperations
V08	0x4337084d9e255ff0702461cf8895ce9e3b5ff108	—
V09	0x433709009B8330FDa32311DF1C2AFA402eD8D009	Latest

Use EntryPointAddresses.Latest (currently V09) unless you need a specific version.

Packages

Package	Description
Nethereum.AccountAbstraction	UserOperation creation, AAContractHandler, SmartAccountBuilder, ERC-7579 modules, gas estimation
Nethereum.AccountAbstraction.Bundler	Full bundler with mempool, validation, reputation, and automatic bundling
Nethereum.AccountAbstraction.Bundler.RpcServer	JSON-RPC server handlers for exposing bundler as an HTTP endpoint
Nethereum.AccountAbstraction.SimpleAccount	SimpleAccount factory for deploying ERC-4337 compatible accounts

Guides

Getting Started

Guide	What You'll Learn
Send a UserOperation	Build, sign, and submit your first ERC-4337 UserOperation step by step
Smart Contracts with AA	Route existing typed contract services through AA with ChangeContractHandlerToAA — the simplest approach
Account Deployment	Deploy smart accounts with SmartAccountBuilder, predict addresses with CREATE2, manage EntryPoint deposits

Advanced

Guide	What You'll Learn
Batching & Paymasters	Execute multiple calls in one UserOperation and sponsor gas with paymasters
Modular Accounts (ERC-7579)	Install validators (multisig, social recovery), executors, and session keys as plug-and-play modules
Run a Bundler	Set up an in-process or standalone bundler with mempool, validation, and RPC server