Gundler

Universal ERC4337 Go Bundler

Gundler is...

• High Performance
• Low Footprint
• Minimal Dependency

RPC Methods

eth_chainId
eth_supportedEntryPoints
eth_sendUserOperation
eth_getUserOperationReceipt

Setup

1. Create a config file (or copy from the example):

cp example.config.json config.json

2. Edit the config file with your settings:

{
  "mode": "DEBUG",
  "ethereum_rpc": "https://rpc.testnet.telos.net",
  "port": 3000,
  "beneficiary": "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266",
  "max_bundle_size": 5,
  "supported_entry_points": [
    "0x5FF137D4b0FDCD49DcA30c7CF57E578a026d2789",
    "0x0000000071727De22E5E9d8BAf0edAc6f37da032",
    "0x4337084D9E255Ff0702461CF8895CE9E3b5Ff108"
  ]
}

3. Run gundler:

go run cmd/main.go

Or specify a custom config file path:

go run cmd/main.go --config /path/to/config.json

Flags

Flag	Description	Default
--config	Path to JSON config file	./config.json

Config File Format

The config file must be a JSON file with the following fields:

Field	Type	Required	Description
mode	string	Yes	Runtime mode: DEBUG, DEV, or PROD (case-insensitive)
ethereum_rpc	string	Yes	Ethereum RPC URL
port	number	No	Port to run the server on (default: 3000)
beneficiary	string	Yes	Beneficiary address
max_bundle_size	number	No	Maximum number of user operations per bundle (default: 5)
supported_entry_points	array[string]	Yes	Array of supported ERC-4337 entry point contract addresses

Runtime Modes

• DEBUG: Enables all debug RPC methods (debug_mempools, debug_pause, debug_clear)
• DEV: Development mode (debug methods disabled)
• PROD: Production mode (debug methods disabled)

Debug RPC Methods

Note: Debug RPC methods are only available when mode is set to DEBUG

debug_mempools

• Returns detailed information about all mempools
• Params: [] (no parameters)
• Response: Array of mempool info containing:
  • label: Version label (MempoolV06, MempoolV07, MempoolV08)
  • address: Entry point address
  • size: Current number of user operations in the mempool
  • userops: Array of all user operations in the mempool

debug_pause

• Toggles pause state of all processors
• When paused, processors stop processing user operations (bundling and submitting)
• User operations can still be added to mempools while paused
• Params: [] (no parameters)
• Response: JSON object with paused field (boolean) indicating new state

debug_clear

• Clears all user operations from all mempools
• Params: [] (no parameters)
• Response: JSON object with cleared count and message fields

Curl Commands

# Healthcheck
curl http://localhost:3000/health

# eth_chainId Method
curl -X POST http://localhost:3000 \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}'

# eth_supportedEntryPoints Method
curl -X POST http://localhost:3000 \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc":"2.0","method":"eth_supportedEntryPoints","params":[],"id":1}'

# eth_sendUserOperation Method
curl -X POST http://localhost:3000 \
    -H "Content-Type: application/json" \
    -d '{
      "jsonrpc": "2.0",
      "method": "eth_sendUserOperation",
      "params": [
        {
          "sender": "0x1234567890123456789012345678901234567890",
          "nonce": "0x1",
          "factory": "0x0000000000000000000000000000000000000000",
          "factoryData": "0x",
          "callData": "0xabcdef",
          "callGasLimit": "0x10000",
          "verificationGasLimit": "0x20000",
          "preVerificationGas": "0x5000",
          "maxFeePerGas": "0x3b9aca00",
          "maxPriorityFeePerGas": "0x3b9aca00",
          "paymaster": "0x0000000000000000000000000000000000000000",
          "paymasterVerificationGasLimit": "0x0",
          "paymasterPostOpGasLimit": "0x0",
          "paymasterData": "0x",
          "signature": "0x1234"
        },
        "0x5FF137D4b0FDCD49DcA30c7CF57E578a026d2789"
      ],
      "id": 1
    }'

# debug_mempools Method (DEBUG mode only)
curl -X POST http://localhost:3000 \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc":"2.0","method":"debug_mempools","params":[],"id":1}'

# debug_pause Method (DEBUG mode only)
curl -X POST http://localhost:3000 \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc":"2.0","method":"debug_pause","params":[],"id":1}'

# debug_clear Method (DEBUG mode only)
curl -X POST http://localhost:3000 \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc":"2.0","method":"debug_clear","params":[],"id":5}'