How to Use a Liquidity Network Bridge (e.g., Hop, Connext)

Detailed Instructions

Begin by connecting a Web3 wallet like MetaMask to the bridge's interface (e.g., app.hop.exchange or app.connext.network). Ensure your wallet is set to the network you are sending from, such as Ethereum Mainnet. In the bridge UI, you will select the source chain, destination chain, and the asset you wish to transfer. For example, you might choose to send USDC from Arbitrum to Polygon. You must then specify the exact transfer amount. It is critical to verify that you have sufficient funds for both the amount and the estimated gas fees on both the source and destination chains. Bridges often support multiple assets like ETH, WETH, USDC, and DAI.

• Sub-step 1: Navigate to the bridge website and click 'Connect Wallet'.
• Sub-step 2: From the dropdowns, select 'Arbitrum' as the source and 'Polygon' as the destination.
• Sub-step 3: Choose 'USDC' and enter an amount like '100.0'.
• Sub-step 4: Review the estimated fees and final received amount displayed by the bridge.

Tip: Always double-check the token contract addresses on the bridge's documentation to avoid scams. For Hop, the canonical USDC address on Arbitrum is 0xFF970A61A04b1cA14834A43f5dE4533eBDDB5CC8.

Detailed Instructions

Before the bridge can move your tokens, you must give it an allowance. This is a standard ERC-20 approval transaction that authorizes the bridge's smart contract to withdraw a specific amount of tokens from your wallet. The approval is a one-time requirement per token and contract, unless you revoke it. You will initiate this transaction directly from the bridge interface, which will prompt your wallet (e.g., MetaMask) for confirmation. Pay close attention to the gas fee for this approval, as it can be high on networks like Ethereum. Some bridges use permit signatures (EIP-2612) for gasless approvals, but a standard transaction is more common.

• Sub-step 1: After entering your amount, click 'Approve USDC' or a similar button.
• Sub-step 2: A MetaMask pop-up will appear. Verify the contract address (e.g., Hop's Arbitrum bridge for USDC: 0x0e0E3d2C5c292161999474247956EF542caBF8dd).
• Sub-step 3: Confirm the transaction. You can check its status on a block explorer like Arbiscan.

Tip: You can set a custom spending cap. For a single transfer, approve only the exact amount to minimize risk. Use a gas tracker to submit the transaction during low-fee periods.

Detailed Instructions

Once the token approval is confirmed, you can initiate the bridge transfer. Click the 'Send' or 'Bridge' button. This action triggers the core bridge mechanism: for a lock-and-mint bridge like Connext, your tokens are locked in a contract on the source chain. For a burn-and-mint or liquidity pool model like Hop, your tokens may be swapped for a bridge-specific hToken (e.g., hUSDC) and burned. Your wallet will prompt you to sign and pay for this transaction. The bridge will provide an estimated completion time, which can range from minutes for optimistic rollups to hours for some security models. You will receive a transaction hash for the source chain.

• Sub-step 1: Click 'Bridge' and review the final summary showing destination, amount, and total fees.
• Sub-step 2: Confirm the transaction in your wallet. The command in the transaction data might look like a call to a function like swapAndSend.
• Sub-step 3: Save the transaction hash (e.g., 0xabc123...) from the confirmation or the bridge's UI.

Tip: Bridges often have a 'Transaction History' or 'Status' page. Bookmark it using your transaction hash to monitor progress. For Hop, you might see a 'Bonder' fee for faster transfers.

Detailed Instructions

The final step is to receive your assets on the destination chain. This process can be automatic or manual. For many bridges, once the source transaction is confirmed and the message relay occurs, the funds will appear in your wallet on the destination network automatically. However, some scenarios require a manual claim transaction. You may need to switch your wallet's network (e.g., to Polygon) and visit the bridge's status page to execute a 'Claim' transaction. This step pays a small gas fee on the destination chain. Always verify the received amount matches the bridge's estimate minus all fees.

• Sub-step 1: Switch your wallet to the destination network (e.g., Polygon Mainnet).
• Sub-step 2: Go to the bridge's transaction status page and locate your transfer using the hash.
• Sub-step 3: If a 'Claim' button is active, click it and confirm the transaction in your wallet.
• Sub-step 4: Check your wallet balance. The USDC should now be visible at the Polygon address 0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174.

Tip: If funds don't appear, check the bridge's support or explorer. For Connext, you can manually call the execute function on the destination chain's ConnextHandler contract with the transaction data provided.

Detailed Instructions

Before initiating a transfer, conduct a thorough route and asset analysis. This involves comparing different liquidity networks (e.g., Hop's canonical bridges vs. AMM pools) and wrapped assets (e.g., hUSDC vs. canonical USDC) to minimize cost and slippage.

• Sub-step 1: Use a bridge aggregator like Socket.tech or Li.Fi to compare total transfer time, fees, and success rates across Hop, Connext, and other protocols for your specific chain pair (e.g., Arbitrum to Polygon).
• Sub-step 2: Evaluate asset representation. Determine if you should bridge the canonical asset (slower, often cheaper) or a liquidity provider (LP) token (faster, may have a fee). On Hop, bridging USDC from Optimism to Arbitrum might offer a choice between a 20-minute canonical route or a 5-minute hUSDC route via an AMM.
• Sub-step 3: Check destination chain liquidity. Ensure the receiving chain's pool has sufficient liquidity for your swap or withdrawal to avoid high slippage. You can check this on the bridge's interface or a block explorer.

Tip: For large transfers, split them into smaller batches to reduce price impact and test the bridge's reliability with a small amount first.

Detailed Instructions

Transaction parameter tuning is crucial for ensuring your transaction succeeds under unpredictable network congestion and price movements. Never rely solely on default settings for significant sums.

• Sub-step 1: Set a custom gas limit and priority fee. For Ethereum mainnet interactions (e.g., initiating a Hop bridge from L1), use a gas tracker like Etherscan's Gas Tracker. You might set a gas limit of 250,000 and a Max Priority Fee of 2.5 Gwei to ensure timely processing.
• Sub-step 2: Define a strict slippage tolerance. In the bridge UI, locate the advanced settings and set a maximum slippage, typically between 0.1% and 0.5%. This prevents your swap on the destination chain from executing at an unacceptable price.
• Sub-step 3: Implement a transaction deadline. Some protocols allow you to set a deadline (in seconds). For example, in a Connext xcall, you can set _relayerFee and a _callback deadline. If the transaction isn't completed within this window, it reverts, protecting you from stale prices.

Tip: When bridging to a new L2, research its native gas token (e.g., MATIC for Polygon) and ensure your wallet has a small amount to pay for the final claim transaction.

Detailed Instructions

Adopt a trust-but-verify approach for every interaction. Bridge interfaces are prime targets for phishing, and smart contracts can be upgraded.

• Sub-step 1: Cross-reference all contract addresses. Before approving a token spend or interacting with a bridge UI, verify the contract address on the project's official documentation or GitHub. For example, the canonical Hop ETH bridge on Optimism is 0x86cA30bEF97fB651b8d866D45503684b90cb3312. Never trust an address from an unofficial source.
• Sub-step 2: Monitor the transaction via the block explorer. After signing, don't just rely on the bridge UI. Take your transaction hash and track it on both the source and destination chain explorers (e.g., Arbiscan for Arbitrum). Look for confirmations and the "Bridged" status event.
• Sub-step 3: Verify the receiving address. Double-check that the to address in the transaction details is yours. For programmable transactions (Connext's xcall), review the _to and _callData parameters for accuracy.

Tip: Bookmark the official bridge URLs and consider using a hardware wallet. Never share your private keys or seed phrase with any "support" agent contacting you.

Detailed Instructions

Post-bridge monitoring and contingency planning are essential, as transactions can sometimes stall or fail due to liquidity issues or network halts.

• Sub-step 1: Use the bridge's status page or SDK. Both Hop and Connext provide tools to query transaction status. For Hop, you can use the getTransferStatus function in their SDK, passing your transaction ID.

javascriptCopy
import { Hop } from '@hop-protocol/sdk';
const hop = new Hop('mainnet');
const status = await hop.getTransferStatus('0xYOUR_TX_HASH');
console.log(status);

• Sub-step 2: Understand the recovery process. If a transaction is stuck (e.g., a Hop bonder hasn't relayed it), you may need to trigger a manual claim or force withdrawal. This often involves calling a specific function on the destination chain contract with proof.
• Sub-step 3: Monitor for protocol updates and incidents. Follow the official project Twitter accounts and Discord announcements. In the event of a critical bug or upgrade, you may need to take specific actions to secure your funds.

Tip: Keep detailed records of all transaction hashes, bridge used, amounts, and timestamps. This is invaluable for troubleshooting or seeking support from the protocol's team.