--- title: Transfer Assets from Ethereum into Polkadot description: A step-by-step guide to bridging assets from Ethereum to Polkadot using the ParaSpell XCM SDK and Snowbridge. categories: - Interoperability url: https://docs.polkadot.com/chain-interactions/send-transactions/interoperability/transfer-assets-into-polkadot/ word_count: 1714 token_estimate: 3263 version_hash: sha256:6829f50b280fd08a21b26f425f1d573d07ed02448f4695c0e5a89a6a120e9fea last_updated: '2026-06-04T16:08:37+00:00' --- # Transfer Assets from Ethereum into Polkadot ## Introduction This guide walks you through transferring tokens from Ethereum to Polkadot using the [ParaSpell XCM SDK](/reference/tools/paraspell/) and [Snowbridge](https://docs.snowbridge.network/). Snowbridge is a trustless, decentralized bridge integrated into the Polkadot protocol that enables secure asset transfers between the Ethereum and Polkadot ecosystems. ### How the Bridge Works The following diagram shows the complete flow when bridging WETH from Ethereum to Polkadot: ```mermaid sequenceDiagram participant User participant Ethereum participant Relayers participant Polkadot User->>Ethereum: 1. Approve & send tokens Ethereum->>Ethereum: Lock tokens Note over Relayers: ~30 min relay Relayers->>Polkadot: 2. Relay message Polkadot->>Polkadot: Verify & mint tokens Polkadot-->>User: 3. Tokens available ``` In this guide, you will: - Set up an Ethereum development environment with the ParaSpell SDK - Approve tokens for the Snowbridge Gateway contract - Build and execute a bridge transfer from Ethereum to Polkadot Hub - Monitor the transfer status ## Prerequisites Before you begin, ensure you have the following: - A basic understanding of [XCM](/parachains/interoperability/get-started/). - Familiarity with JavaScript/TypeScript and Ethereum development. - [Node.js](https://nodejs.org/) v18 or higher and npm installed. - An Ethereum wallet with WETH tokens. See [Prepare Tokens for Bridging](#prepare-tokens-for-bridging) for instructions to wrap ETH if needed. - A Polkadot account to receive the bridged assets. ## Prepare Tokens for Bridging To bridge ETH, you need to wrap it into WETH first. The WETH contract on Ethereum mainnet is: ``` 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 ``` !!!note "Why WETH instead of ETH?" Snowbridge only supports ERC-20 tokens—it cannot bridge native ETH directly. The bridge uses a standardized token interface to lock assets on Ethereum and mint corresponding representations on Polkadot. Since native ETH doesn't conform to the ERC-20 standard, you must first wrap it into WETH (Wrapped ETH), an ERC-20-compliant token pegged 1:1 to ETH. You can wrap ETH by: 1. Visiting the [WETH contract on Etherscan](https://etherscan.io/address/0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2#writeContract) 2. Connecting your wallet 3. Calling the `deposit` function with the amount of ETH you want to wrap ## Initialize Your Project Follow these steps to setup and initialize your project: 1. Create the project folder using the following commands: ```bash mkdir eth-to-polkadot-bridge && \ cd eth-to-polkadot-bridge ``` 2. Initialize the JavaScript project: ```bash npm init -y && npm pkg set type=module ``` Install dev dependencies: ```bash npm install --save-dev @types/node tsx typescript ``` Sending assets from Ethereum to Polkadot requires the PJS version of the ParaSpell SDK. Install the necessary dependencies using the following command: ```bash npm install @paraspell/sdk-pjs@13.2.2 @polkadot/api@16.5.6 @polkadot/types@16.5.6 ethers@6.16.0 ``` Now add the following setup code to `index.ts`: ```ts title="index.ts" import { EvmBuilder, getTokenBalance, approveToken, getBridgeStatus } from '@paraspell/sdk-pjs'; import { ethers } from 'ethers'; // Ethereum mainnet RPC endpoint (use your own API key) const ETH_RPC = 'https://eth-mainnet.g.alchemy.com/v2/INSERT_API_KEY'; // WETH contract address on Ethereum mainnet const WETH_ADDRESS = '0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2'; // WETH has 18 decimals const WETH_UNITS = 1_000_000_000_000_000_000n; // Amount to bridge: 0.001 WETH (raw units as bigint) const AMOUNT = WETH_UNITS / 1000n; // Your Polkadot address to receive the bridged tokens (SS58 format) const RECIPIENT_ADDRESS = 'INSERT_YOUR_POLKADOT_ADDRESS'; // Connect to Ethereum mainnet async function getProviderAndSigner(); } ``` Replace `INSERT_YOUR_POLKADOT_ADDRESS` with your Polkadot account address (SS58 format) that will receive the bridged tokens on Polkadot Hub. !!!warning "Security Warning" Never commit private keys or seed phrases to production code. Use environment variables or secure key management systems. ## Approve Tokens for Bridging Before bridging ERC-20 tokens, you must approve the Snowbridge Gateway contract to spend your tokens. The ParaSpell SDK provides the following helper functions for approving spending: ```ts title="index.ts" async function approveTokens() = await getProviderAndSigner(); // Check current WETH balance const balance = await getTokenBalance(signer, 'WETH'); console.log(`Current WETH balance: ${balance}`); if (BigInt(balance) === 0n)`); process.exit(1); } // Approve the Snowbridge Gateway contract to spend WETH const { result: approveTx } = await approveToken(signer, AMOUNT, 'WETH'); console.log(`Approval transaction hash: ${approveTx.hash}`); // Wait for confirmation await approveTx.wait(); console.log('Token approval confirmed!'); } ``` Run the approval script: ```bash npx tsx index.ts ``` You will see output confirming the token balance and approval similar to the following:
npx tsx index.ts Current WETH balance: 0.05 Approval transaction hash: 0x1a2b3c4d5e6f7890abcdef1234567890abcdef1234567890abcdef1234567890 Token approval confirmed!
## Build and Execute the Bridge Transfer Now build and execute the bridge transfer from Ethereum to Polkadot Hub: ```ts title="index.ts" async function bridgeToPolkadot() = await getProviderAndSigner(); console.log('Building bridge transaction...'); console.log(`Bridging ${AMOUNT} WETH to Polkadot Hub`); console.log(`Recipient: ${RECIPIENT_ADDRESS}`); // Build and execute the bridge transfer // Note: 'AssetHubPolkadot' is the SDK identifier for Polkadot Hub const txHash = await EvmBuilder(provider) .from('Ethereum') .to('AssetHubPolkadot') .currency({ symbol: 'WETH', amount: AMOUNT, }) .recipient(RECIPIENT_ADDRESS) .signer(signer) .build(); console.log('Bridge transaction submitted!'); console.log(`Transaction hash: ${txHash}`); console.log('Transfer will arrive in approximately 30 minutes.'); // Wait for Ethereum confirmation const receipt = await provider.waitForTransaction(txHash); console.log( ``` Comment out the `approveTokens()` function and run the transfer: ```bash npx tsx index.ts ``` After submitting the transaction, you will see the Ethereum transaction hash included in the terminal output similar to the following:
npx tsx index.ts Building bridge transaction... Bridging 1000000000000000 WETH to Polkadot Hub Recipient: 5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY Bridge transaction submitted! Transaction hash: 0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890 Transfer will arrive in approximately 30 minutes. Ethereum transaction confirmed! Waiting for bridge relay...
## Monitor the Transfer Bridge transfers from Ethereum to Polkadot take approximately 30 minutes. You can monitor the transfer status in several ways: - **Snowbridge App** - Visit [app.snowbridge.network](https://app.snowbridge.network/) to check the transfer history - **Etherscan** - Track your Ethereum transaction on [etherscan.io](https://etherscan.io/) - **Polkadot.js Apps** - Monitor incoming transfers on [Polkadot Hub](https://polkadot.js.org/apps/?rpc=wss%3A%2F%2Fpolkadot-asset-hub-rpc.polkadot.io#/accounts) You can also check the bridge status programmatically: ```ts title="index.ts" bridgeToPolkadot(); async function checkBridgeStatus() from '@paraspell/sdk-pjs'; // Get assets supported for Ethereum → Polkadot Hub transfers const supportedAssets = getSupportedAssets('Ethereum', 'AssetHubPolkadot'); console.log('Supported assets:', supportedAssets.map(a => a.symbol)); ``` Running this script will return a list of supported assets in the terminal similar to the following:
npx tsx get-supported-assets.ts Supported assets: [ 'WETH', 'WBTC', 'USDC', 'USDT', 'DAI', 'SHIB', 'LINK', 'AAVE', 'wstETH', 'tBTC', 'PEPE', 'EURC', 'MYTH', 'TRAC', 'KILT', 'DOT', ... and more ]
Common supported tokens on Polkadot Hub include: | Token | Symbol | Description | |-------|--------|-------------| | Wrapped Ether | WETH | Ethereum's native token wrapped as ERC-20 | | Wrapped Bitcoin | WBTC | Bitcoin wrapped as an ERC-20 token | | Shiba Inu | SHIB | Popular ERC-20 meme token | To transfer to a different destination, change the `.to()` parameter and verify the asset is supported using the following code: ```ts title="index.ts" // Check if WETH is supported on Hydration const hydrationAssets = getSupportedAssets('Ethereum', 'Hydration'); const wethSupported = hydrationAssets.some(a => a.symbol === 'WETH'); if (wethSupported)) .recipient(recipientAddress) .signer(signer) .build(); } ```
npx tsx bridge-to-hydration.ts WETH supported on Hydration: true Building bridge transaction to Hydration... Bridge transaction submitted! Transaction hash: 0x1234...abcd
???- code "Complete `index.ts` script" ```typescript title="index.ts" import { EvmBuilder, getTokenBalance, approveToken, getBridgeStatus } from '@paraspell/sdk-pjs'; import { ethers } from 'ethers'; // Ethereum mainnet RPC endpoint (use your own API key) const ETH_RPC = 'https://eth-mainnet.g.alchemy.com/v2/INSERT_API_KEY'; // WETH contract address on Ethereum mainnet const WETH_ADDRESS = '0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2'; // WETH has 18 decimals const WETH_UNITS = 1_000_000_000_000_000_000n; // Amount to bridge: 0.001 WETH (raw units as bigint) const AMOUNT = WETH_UNITS / 1000n; // Your Polkadot address to receive the bridged tokens (SS58 format) const RECIPIENT_ADDRESS = 'INSERT_YOUR_POLKADOT_ADDRESS'; // Connect to Ethereum mainnet async function getProviderAndSigner(); } async function approveTokens() = await getProviderAndSigner(); // Check current WETH balance const balance = await getTokenBalance(signer, 'WETH'); console.log(`Current WETH balance: ${balance}`); if (BigInt(balance) === 0n)`); process.exit(1); } // Approve the Snowbridge Gateway contract to spend WETH const { result: approveTx } = await approveToken(signer, AMOUNT, 'WETH'); console.log(`Approval transaction hash: ${approveTx.hash}`); // Wait for confirmation await approveTx.wait(); console.log('Token approval confirmed!'); } approveTokens(); async function bridgeToPolkadot() = await getProviderAndSigner(); console.log('Building bridge transaction...'); console.log(`Bridging ${AMOUNT} WETH to Polkadot Hub`); console.log(`Recipient: ${RECIPIENT_ADDRESS}`); // Build and execute the bridge transfer // Note: 'AssetHubPolkadot' is the SDK identifier for Polkadot Hub const txHash = await EvmBuilder(provider) .from('Ethereum') .to('AssetHubPolkadot') .currency({ symbol: 'WETH', amount: AMOUNT, }) .recipient(RECIPIENT_ADDRESS) .signer(signer) .build(); console.log('Bridge transaction submitted!'); console.log(`Transaction hash: ${txHash}`); console.log('Transfer will arrive in approximately 30 minutes.'); // Wait for Ethereum confirmation const receipt = await provider.waitForTransaction(txHash); console.log( `Ethereum transaction confirmed in block ${receipt?.blockNumber}. Waiting for bridge relay...`, ); } bridgeToPolkadot(); async function checkBridgeStatus() checkBridgeStatus(); ``` !!!info "Transfer Assets Out of Polkadot" To transfer assets out of Polkadot, you can use the ParaSpell XCM SDK to build and execute a bridge transfer from Polkadot to Ethereum. Check out the [Polkadot to Ethereum](https://paraspell.github.io/docs/xcm-sdk/send-xcm.html#polkadot-ethereum-transfer) section of the ParaSpell XCM SDK documentation. ## Where to Go Next - **External Documentation** - Dive deeper into the [ParaSpell XCM SDK](https://paraspell.github.io/docs/xcm-sdk/getting-started.html) and [Snowbridge](https://docs.snowbridge.network/) documentation resources. - **Learn about XCM** - Understand the underlying protocol by visiting the [Get Started with XCM](/parachains/interoperability/get-started/) guide