Aa Bundler

Run an ERC-4337 Bundler

Nethereum includes a full ERC-4337 bundler — collects UserOperations, validates them, manages a mempool with reputation tracking, and submits bundles to the EntryPoint.

When to Use This

• User wants to run their own bundler instead of using a third-party service
• User is building an application chain that needs an integrated bundler
• User needs to configure bundler settings (validation, mempool, reputation)
• User wants a JSON-RPC endpoint for the bundler

Packages

dotnet add package Nethereum.AccountAbstraction.Bundler
dotnet add package Nethereum.AccountAbstraction.Bundler.RpcServer  # for JSON-RPC endpoint

Quick Start

using Nethereum.AccountAbstraction.Bundler;
using Nethereum.Web3;
using Nethereum.Web3.Accounts;

var web3 = new Web3(new Account(privateKey), "http://localhost:8545");

var config = BundlerConfig.CreateAppChainConfig(
    entryPoint: EntryPointAddresses.Latest,
    beneficiary: "0xBeneficiaryAddress");

var bundlerService = new BundlerService(web3, config);

// Submit a UserOperation
string userOpHash = await bundlerService.SendUserOperationAsync(
    packedUserOp, EntryPointAddresses.Latest);

// Trigger immediate bundling
BundleResult result = await bundlerService.ExecuteBundleAsync();

// Check receipt
var receipt = await bundlerService.GetUserOperationReceiptAsync(userOpHash);

Configuration Presets

var appConfig = BundlerConfig.CreateAppChainConfig(entryPoint, beneficiary);
var stdConfig = BundlerConfig.CreateStandardConfig(entryPoint, beneficiary);
var prodConfig = BundlerConfig.CreateProductionConfig(entryPoint, beneficiary);

Key Config Properties

JSON-RPC Server

using Nethereum.AccountAbstraction.Bundler.RpcServer;

var rpcServer = new RpcServer();
rpcServer.AddBundlerHandlers(bundlerService);

// Or create bundler from config:
rpcServer.AddBundlerHandlers(web3, config);

Standard RPC Methods

Debug Methods

Reputation and Staking

var config = BundlerConfig.CreateProductionConfig(entryPoint, beneficiary);
config.WhitelistedAddresses.Add("0xYourPaymaster");  // trust your paymaster
config.BlacklistedAddresses.Add("0xBadFactory");      // block bad actors

Common Mistakes

• No beneficiary — required, receives bundler fees
• Wrong EntryPoint — bundler only accepts ops targeting SupportedEntryPoints
• AutoBundle=0 without manual bundling — ops pile up, never submitted
• UnsafeMode in production — skips all validation, wastes gas on bad ops

For full documentation, see: https://docs.nethereum.com/docs/account-abstraction/guide-run-bundler