SignTxn

A utility for signing Ethereum transactions using different EIP standards (EIP-155, EIP-1559, EIP-2930).

Overview

SignTxn is a JavaScript-based tool that allows you to sign Ethereum transactions offline using different transaction types:

• EIP-155: Legacy transactions with replay protection
• EIP-1559: Fee market change transactions (London fork)
• EIP-2930: Optional access lists transactions (Berlin fork)

This tool is useful for developers who need to create and sign transactions for testing, debugging, or interacting with Ethereum networks.

Project Structure

The project is organized into the following directories:

• scripts/: Contains the transaction signing scripts for different EIP standards
  • sign-eip155-tx.js: Legacy transaction signing (EIP-155)
  • sign-eip1559-tx.js: Fee market transaction signing (EIP-1559)
  • sign-eip2930-tx.js: Access list transaction signing (EIP-2930)
• helpers/: Contains utility functions used by the scripts
  • utils.js: Common utility functions for parsing method parameters and getting nonce
• abi/: Contains ABI definitions for contract interactions

Installation

1. Clone the repository:

   git clone https://github.com/yasenltd/SignTxn.git
   cd SignTxn
   

2. Install dependencies:

   npm install
   

3. Configure your environment variables by copying the .example.env file to .env and updating the values (see Configuration section below).

Usage

The repository contains three scripts for signing different types of transactions:

1. Sign EIP-155 Transaction (Legacy)

node scripts/sign-eip155-tx.js

2. Sign EIP-1559 Transaction (Fee Market)

node scripts/sign-eip1559-tx.js

3. Sign EIP-2930 Transaction (Access Lists)

node scripts/sign-eip2930-tx.js

Each script will output the signed transaction as a hexadecimal string that can be submitted to an Ethereum network.

Configuration

The repository includes a .example.env file with placeholder values. Copy this file to create your own .env file:

cp .example.env .env

Then edit the .env file to set your own values for the following variables:

PRIVATE_KEY=your_private_key_here
VALUE=0.001
CHAIN_ID=
GAS_LIMIT=
TARGET_CHAIN_ID=
TO_ADDRESS=0xYourTargetAddressHere
RPC_PROVIDER=https://your-rpc-endpoint.io

# ABI and Method Configuration
USE_METHOD=false
ABI_PATH=./abi/contract.json
METHOD_NAME=deposit
# Optional: Override recipient address (defaults to wallet address if not specified)
# RECIPIENT=0xYourRecipientAddress
# Optional: Override method parameters (JSON array format)
# METHOD_PARAMS=["0xYourRecipientAddress", "0x4268"]

Configuration Options

Variable	Description	Default
PRIVATE_KEY	Your Ethereum private key (without 0x prefix)	Required
VALUE	Amount of ETH to send (in ETH)	0.0
CHAIN_ID	Chain ID of the network	1
GAS_LIMIT	Gas limit for the transaction	21000
TARGET_CHAIN_ID	Target chain ID for cross-chain operations	0
TO_ADDRESS	Recipient address (contract or EOA)	Required
RPC_PROVIDER	RPC endpoint URL	Required
USE_METHOD	Whether to create a contract method call	false
ABI_PATH	Path to the contract ABI JSON file	./abi/contract.json
METHOD_NAME	Contract method name to call	methodName
RECIPIENT	Recipient address for the method call	Wallet address
METHOD_PARAMS	JSON array of parameters for the method call	[RECIPIENT, TARGET_CHAIN_ID]

Examples

Simple ETH Transfer

To sign a simple ETH transfer transaction:

1. Configure your .env file:

   PRIVATE_KEY=your_private_key_here
   VALUE=0.01
   TO_ADDRESS=0xRecipientAddressHere
   RPC_PROVIDER=https://mainnet.infura.io/v3/your-project-id
   CHAIN_ID=1
   USE_METHOD=false
   

2. Run one of the signing scripts:

   node scripts/sign-eip1559-tx.js
   

Contract Method Call

To sign a transaction that calls a contract method:

1. Configure your .env file:

   PRIVATE_KEY=your_private_key_here
   VALUE=0
   TO_ADDRESS=0xContractAddressHere
   RPC_PROVIDER=https://mainnet.infura.io/v3/your-project-id
   CHAIN_ID=1
   USE_METHOD=true
   METHOD_NAME=transfer
   METHOD_PARAMS=["0xRecipientAddress", "1000000000000000000"]
   

2. Run one of the signing scripts:

   node scripts/sign-eip1559-tx.js
   

Ethereum JSON-RPC API Calls

The following curl commands can be used to interact with Ethereum nodes:

eth_sendRawTransaction

curl -X POST https://testnet.rpc.neuraprotocol.io \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_sendRawTransaction",
    "params": ["txnSignatureHex"],
    "id": 1
  }'

eth_getTransactionCount

curl -X POST https://testnet.rpc.neuraprotocol.io \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_getTransactionCount",
    "params": ["address", "pending"],
    "id": 1
  }'

eth_getCode

curl -X POST https://testnet.rpc.neuraprotocol.io \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_getCode",
    "params": ["address", "latest"],
    "id": 1
  }'

Method Reference Table

Method	Purpose	Input Required
eth_sendRawTransaction	Send a signed TX to the chain	Raw signed TX hex
eth_getTransactionCount	Get the correct nonce for an account	Address, block tag
eth_getCode	Check if address is a contract	Address, block tag (latest)

Security Notes

• Never commit your .env file with your private key to version control (it's already added to .gitignore)
• This tool is for development and testing purposes only
• Always verify the transaction details before submitting to a network