This small Ruby gem makes manipulations with Ethereum ERC20 tokens as simple as possible, when you have a provider of JSON-RPC and WebSockets Ethereum APIs, such as Infura, GetBlock, or Alchemy:
# Create a wallet:
require 'erc20'
w = ERC20::Wallet.new(
contract: ERC20::Wallet.USDT, # hex of it
host: 'mainnet.infura.io',
http_path: '/v3/<your-infura-key>',
ws_path: '/ws/v3/<your-infura-key>',
log: $stdout
)
# Check how many ERC20 tokens are on the given address:
usdt = w.balance(address)
# Send a few ERC20 tokens to someone and get transaction hash:
hex = w.pay(private_key, to_address, amount)
# Stay waiting, and trigger the block when new ERC20 payments show up:
addresses = ['0x...', '0x...'] # only wait for payments to these addresses
w.accept(addresses) do |event|
puts event[:txn] # hash of transaction
puts event[:amount] # how much, in tokens (1000000 = $1 USDT)
puts event[:from] # who sent the payment
puts event[:to] # who was the receiver
endYou can also check ETH balance and send ETH transactions:
# Check how many ETHs are on the given address:
eth = w.eth_balance(address)
# Send a few ETHs to someone and get transaction hash:
hex = w.eth_pay(private_key, to_address, amount)To check the price of a gas unit and the expected cost of a payment:
# How many gas units required to send this payment:
units = w.gas_estimate(from, to, amount)
# What is the price of a gas unit, in gwei:
gwei = w.gas_priceTo generate a new private key, use eth:
require 'eth'
key = Eth::Key.new.private_hexTo convert a private key to a public address:
public_hex = Eth::Key.new(priv: key).addressTo connect to the server via HTTP proxy with basic authentication:
w = ERC20::Wallet.new(
host: 'go.getblock.io',
http_path: '/<your-rpc-getblock-key>',
ws_path: '/<your-ws-getblock-key>',
proxy: 'http://jeffrey:[email protected]:3128' # here!
)You can use squid-proxy Docker image to set up your own HTTP proxy server.
Of course, this library works with Polygon, Optimism, and other EVM compatible blockchains.
This gem also provides a command line tool for sending ETH and ERC20 payments and checking balances.
First, you install it, via gem:
gem install erc20Then, run it:
erc20 --helpUsage should be straightforward. If you have questions, please submit an issue.
You can use the ERC20::FakeWallet class that behaves exactly like
ERC20::Wallet, but doesn't make any network connections to the provider.
Additionally, it records all requests sent to it:
require 'erc20'
w = ERC20::FakeWallet.new
w.pay(priv, address, 42_000)
assert w.history.include?({ method: :pay, priv:, address:, amount: 42_000 })Read these guidelines. Make sure your build is green before you contribute your pull request. You will need to have Ruby 3.2+ and Bundler installed. Then:
bundle update
bundle exec rakeIf it's clean and you don't see any error messages, submit your pull request.