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Substrate To EVM Token Transfer

Sygma SDK Substrate to EVM (Tangle to Sepolia) Asset Transfer Example​

This is an example script that demonstrates the functionality of the SDK using the Sygma ecosystem. The script showcases a Substrate Asset transfer between a Substrate network and an EVM network using the Sygma SDK.

Prerequisites​

Before running the script, ensure that you have the following:

  • Node.js installed on your machine (v18.20.4)
  • Yarn (version 3.4.1 or higher)
  • A Substrate development wallet funded with TANGLE TNT tokens; you may wish to run the EVM-to-Substrate example first to preload TNT tokens into a Substrate wallet
  • The 12-word mnemonic for your Substrate development wallet
  • An Ethereum wallet to receive tokens into (the example presets an existing wallet address already)
  • A Substrate provider (in case the hardcoded WSS within the script does not work)

Getting started​

1. Clone the repository​

To get started, clone this repository to your local machine with:

git clone https://github.com/sygmaprotocol/sygma-sdk.git
cd sygma-sdk/

2. Install dependencies​

Install the project dependencies by running:

yarn install

3. Build the sdk​

To start the example you need to build the sdk first with:

yarn build

Obtaining sygUSD Tokens​

The RESOURCE_ID_SYGMA_USD represents the ID for sygUSD tokens in the Sygma protocol. You will need sygUSD testnet tokens to complete this transfer. If you are transferring a different asset, you may need to replace this ID with the appropriate resource ID.

You can obtain testnet sygUSD tokens for the Tangle testnet by visiting the Sygma Testnet Faucet.

Usage​

This example uses the dotenv module to import the 12-word private mnemonic. To run the example, you will need to configure your environment variable to include your test development account's 12-word seed. A .env.sample is provided as a template.

DO NOT COMMIT YOUR MNEMONIC WITH REAL FUNDS TO GITHUB. DOING SO COULD RESULT IN COMPLETE LOSS OF YOUR FUNDS.

Environment Variables​

Create a .env file in the substrate-to-evm example folder:

touch .env

The file should contain the following environment variables:

  • PRIVATE_MNEMONIC: The 12-word mnemonic for your Substrate wallet.
  • SOURCE_SUBSTRATE_RPC_URL: The WebSocket URL of the Substrate network (Tangle in this example).
  • RECIPIENT_ADDRESS: The destination EVM address that will receive the tokens (Sepolia testnet in this example).
  • SYGMA_ENV: The Sygma environment you’re using, e.g., testnet.

Here’s an example of the .env file:

PRIVATE_MNEMONIC="YOUR TWELVE WORD MNEMONIC HERE"
SOURCE_SUBSTRATE_RPC_URL="wss://rpc.tangle.tools"
RECIPIENT_ADDRESS="YOUR EVM ADDRESS"
SYGMA_ENV="testnet"

Obtaining Your 12-Word Mnemonic​

To create a Substrate wallet and obtain the 12-word mnemonic, follow this Polkadot wallet guide.

Replace between the quotation marks your 12-word mnemonic:

PRIVATE_MNEMONIC="YOUR TWELVE WORD MNEMONIC HERE WITH SPACES"

Run the example​

To send a Substrate token to an EVM chain example transfer run:

yarn run transfer

The example will use @polkadot/keyring in conjunction with the sygma-sdk to create a transfer from Tangle to Sepolia.

Replace the placeholder values in the .env file with your own Substrate wallet mnemonic, and your own destination EVM address within the script.

Monitoring the Transfer​

Once the transaction is finalized, you can view the transaction details in the Sygma Explorer.

Script Functionality​

This example script performs the following steps:

  1. Initializes the SDK: It connects to the Substrate node via WebSocket and initializes the SDK.
  2. Retrieves Supported Domains and Resources: It fetches the list of supported domains (Tangle and Sepolia in this case) and resources like sygUSD.
  3. Constructs a Transfer Object: A transfer object is built, specifying the token amount, the source, and destination chains (Tangle and Sepolia).
  4. Fetches Transfer Fees: The SDK calculates the fees required for the transfer.
  5. Signs and Sends the Transaction: The transfer transaction is signed with your Substrate account and broadcasted to the network.
  6. Monitors Transaction Status: The script logs transaction statuses such as InBlock and Finalized. It provides a link to the Sygma Explorer where the transaction can be monitored.