Get Started

This guide shows how to install the package, create an EVM account, instantiate the bridge protocol, use a read-only account, and review supported chains.

Install the package

Prerequisites

• Node.js: version 18 or higher.
• npm: usually bundled with Node.js.

You can add the published package to your project from npm: @tetherto/wdk-protocol-bridge-usdt0-evm.

npm install @tetherto/wdk-protocol-bridge-usdt0-evm @tetherto/wdk-wallet-evm

Create an EVM account

You can construct a signing account using new WalletAccountEvm(seed, path, config?) from @tetherto/wdk-wallet-evm with an RPC provider:

import { WalletAccountEvm } from '@tetherto/wdk-wallet-evm'

const seedPhrase = 'abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about'

const account = new WalletAccountEvm(seedPhrase, "0'/0/0", {
  provider: 'https://eth.drpc.org'
})

Instantiate the bridge protocol

You can create a Usdt0ProtocolEvm instance with the new Usdt0ProtocolEvm(account, config?) constructor. Optional bridgeMaxFee rejects a bridge when the implementation's combined fee value is at or above the cap:

import Usdt0ProtocolEvm from '@tetherto/wdk-protocol-bridge-usdt0-evm'

const bridgeProtocol = new Usdt0ProtocolEvm(account, {
  bridgeMaxFee: 1000000000000000n
})

For standard EVM accounts, fee and bridgeFee are source-chain native base units. Starting in beta.10, ERC-4337 bridgeFee also uses source-native base units. Token-paid gas still reports fee in paymaster-token units, so read Fee units and bridgeMaxFee before setting a cap for that mode.

Use a read-only account (optional)

For quotes without signing, create a WalletAccountReadOnlyEvm for the source address and pass it to Usdt0ProtocolEvm:

import { WalletAccountReadOnlyEvm } from '@tetherto/wdk-wallet-evm'

const readOnlyAccount = new WalletAccountReadOnlyEvm(await account.getAddress(), {
  provider: 'https://eth.drpc.org'
})
const readOnlyBridge = new Usdt0ProtocolEvm(readOnlyAccount)

You can now call quoteBridge() with your route options. The source address needs any allowance and balance required by the route's gas estimate; a read-only account cannot grant that allowance. Calling bridge() on this instance rejects before sending a transaction.

When the signing session ends, clear the directly constructed account's key material:

account.dispose()

Supported chains

Bridge operations use EVM source chains listed in the API reference. A configured EVM destination must have a matching USD₮0 or XAU₮0 contract for the selected token. Solana (EID 30168), TON (EID 30343), and TRON (EID 30420) are also configured as destinations. Use getSupportedTokens() to discover configured EVM token descriptors; it does not return these non-EVM destination-only entries. For every route, call quoteBridge() to verify the exact source-token and destination pair.

Source chains (EVM, targetChain keys)

ERC-4337 helper workflows are available when the source chain is Ethereum, Arbitrum, Plasma, or Polygon. Other listed source chains support standard EVM accounts only. See Bridge with ERC-4337.

Non-EVM destinations

Next Steps

Run a standard EVM-to-EVM transfer with Bridge tokens, or use Bridge with ERC-4337 for gasless flows on supported networks.

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