Bridging EVM to Casper

This guide walks you through bridging ERC-20 tokens from an EVM chain (Ethereum, Base, etc.) to Casper Network.

Overview

When you bridge from EVM to Casper:

1. Lock: Your ERC-20 tokens are locked in the MultiSigLocker contract
2. Finality: The bridge waits for Ethereum finality (~13 minutes)
3. Attestation: Relayers verify the lock event and collect signatures
4. Mint: CEP-18 tokens are minted to your Casper address

Prerequisites

• Both wallets connected (see Connecting Wallets)
• ERC-20 tokens to bridge (see Getting Testnet Tokens)
• ETH for gas fees on the source chain
• Small bridge fee (0.0001 ETH)

Step-by-Step Guide

Step 1: Select Source Network

1. Go to astralbeam.io
2. In the "From" section, ensure an EVM network is selected
3. Click the network selector to change networks if needed
4. Available networks: Ethereum (Sepolia), Base (Sepolia), etc.

Step 2: Select Token

1. Click "Select token" in the token input area
2. A modal will display available bridgeable tokens
3. Choose the token you want to bridge (e.g., USDC, WETH, LINK)
4. Your token balance will be displayed

Step 3: Enter Amount

1. Enter the amount of tokens to bridge
2. The interface will show:
   • Your available balance
   • Estimated receive amount on Casper
3. Ensure you have enough tokens and don't exceed your balance

Step 4: Review Transaction

1. Click "Review Bridged Transfer"
2. A modal displays the transaction summary:

1. Verify all details are correct

Step 5: Approve Token Spending

1. Click "Start Bridged Transfer"
2. First Transaction - Approval:
   • MetaMask will popup requesting token approval
   • This allows the locker contract to spend your tokens
   • Review the approval amount
   • Click "Confirm" in MetaMask
3. Wait for the approval transaction to confirm

Step 6: Confirm Lock Transaction

1. Second Transaction - Lock:
   • MetaMask will popup for the lock transaction
   • This locks your tokens in the bridge contract
   • The transaction includes a 0.0001 ETH bridge fee
   • Click "Confirm" in MetaMask
2. Wait for the lock transaction to confirm

Step 7: Wait for Finality

After the lock transaction confirms:

1. The modal shows "Wait for Finality" as active
2. Why wait? Ethereum needs ~64 blocks (~13 minutes) for finality
3. This protects against chain reorganizations
4. Progress indicator shows estimated time remaining

You can safely close the modal - your transaction is tracked automatically.

Step 8: Relayer Processing

Once finality is reached:

1. The bridge's independent relayers detect your finalized deposit
2. Each relayer verifies it independently
3. Once enough approvals are collected, the mint is submitted to Casper

Step 9: Receive Tokens on Casper

1. The leader relayer submits the mint transaction
2. CEP-18 tokens are minted to your Casper address
3. The modal shows "Completed" status
4. View your tokens in Casper Wallet or CSPR.live

Transaction Progress Steps

Viewing Your Bridged Tokens

On CSPR.live

1. Go to testnet.cspr.live
2. Search for your Casper account
3. Navigate to "Tokens" tab
4. Your bridged CEP-18 tokens will appear

In Casper Wallet

1. Open Casper Wallet extension
2. Your token balance should update automatically
3. If not visible, you may need to add the token manually

Troubleshooting

Transaction Stuck on "Approval"

• Check MetaMask for pending requests
• Ensure you have enough ETH for gas
• Try increasing gas price if network is congested

Transaction Stuck on "Lock"

• Verify approval transaction completed
• Check MetaMask for the second transaction request
• Ensure sufficient ETH for gas + 0.0001 ETH fee

Long Finality Wait

• Ethereum finality takes ~13 minutes (64 blocks)
• This is normal and ensures security
• Progress is saved - you can close and return later

Tokens Not Appearing on Casper

• Wait for the full process to complete
• Check the Transactions page for status
• Verify the correct Casper address was used
• Check CSPR.live for your account's token balances

Gas and Fees

Example: Bridging 10 USDC

1. Connect MetaMask (Sepolia) and Casper Wallet
2. Select "Ethereum (Sepolia)" as source
3. Select USDC from token list
4. Enter "10" as amount
5. Review: 10 USDC → 10 USDC (CEP-18)
6. Approve USDC spending in MetaMask
7. Confirm lock transaction in MetaMask
8. Wait ~15-20 minutes total
9. Receive 10 USDC (CEP-18) on Casper