⏩
⏩
⏩
⏩
Hyperlane Docs
v2
Search
⌃K

Accounts

This tutorial demonstrates how to:
You can also check out the hyperlane-quickstart repo for running this out of the box.

Inputs

  • $DESTINATION_DOMAIN: The domain ID of the destination chain. Domain IDs can be found here.
  • $RECIPIENT: The address of the TestRecipient contract on the destination chain, 0x36FdA966CfffF8a9Cdc814f546db0e6378bFef35

Make a call

Sending a message is a simple matter of calling InterchainAccountRouter.dispatch(). This function can be called easily using Etherscan+Metamask or cast.
Using Metamask
Using cast
  1. 1.
    Navigate to the InterchainAccountRouter 0xE0Be420779cAd6E2bEA1E4F7C02F996D9ED1fCB5 contract page on Etherscan (or whatever chain you want to send from)
  2. 2.
    Under the Contract tab, find the Write Contract button.
  3. 3.
    Click on the Connect to Web3 button to connect your Wallet (i.e. Metamask). Make sure that you are on the correct network.
  4. 4.
    Expand the second dispatch box (There are different overloads for dispatch, one with direct arguments and one with the Call structs).
  5. 5.
    For destination domain, enter $DESTINATION_DOMAIN. You can find some here, or you could use 137 to send to Polygon.
  6. 6.
    For the target argument, enter the $RECIPIENT
  7. 7.
    For the data argument, enter the ABI-encoded function call to the $RECIPIENT. To call TestRecipient's fooBar(uint256,string):
    1. 1.
      ➜ cast calldata "fooBar(uint256,string)" 1 "HelloWorld from an ICA"
      which generates 0xf07c1f4700000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000001648656c6c6f576f726c642066726f6d20616e2049434100000000000000000000
      You can use your preferred abi encoding tool (like https://abi.hashex.org/) as well
  8. 8.
    Submit the transaction via your wallet/Metamask
​
You can call the InterchainAccountRouter directly using cast. Make sure that you have a valid RPC URL for the origin chain and a private key with which you can pay for gas.
cast send 0xE0Be420779cAd6E2bEA1E4F7C02F996D9ED1fCB5 'dispatch(uint32, (address,bytes)[])' $DESTINATION_DOMAIN "[($RECIPIENT,$(cast calldata "fooBar(uint256,string)" 1 "HelloWorld from an ICA via cast"))]" --rpc-url $RPC_URL --private-key $PRIVATE_KEY
Next, you must pay for interchain gas in the following section.
If you view the transaction on a block explorer, you should be able to see the Dispatch event. You can see an example message sending transaction here.

Pay For Interchain Gas

For a message to be delivered by an off-chain relayer, the message must pay interchain gas on the origin chain to cover the destination chain transaction costs. This is done by calling the payForGas function of an "Interchain Gas Paymaster" contract, which lets you pay a relayer to deliver a message on your behalf.
This payForGas call would typically be done by a smart contract that would first dispatch the message and immediately pay for gas, but because we dispatched the message from an externally owned account (EOA), we need to pay for gas with a separate transaction.

Inputs

  • $IGP_ADDRESS : The address of the DefaultIsmInterchainGasPaymaster contract address on the origin chain.
  • $DESTINATION_DOMAIN: The domain ID of the destination chain. Domain IDs can be found here. This should be the same destination domain you used when sending the message.
  • $MESSAGE_ID: This is a 0x-prefixed hexadecimal 32-byte identifier of your message that you just dispatched.
    • This is returned by the InterchainAccountRouter.dispatch() function, but for our purposes this can most easily be found in a block explorer. Navigate to the transaction where you previously called InterchainAccountRouter.dispatch() in a block explorer, open the "Logs" tab, and find the DispatchId log. The "Topic 1" is your message ID. Use the dropdown to select "Hex", and use this value. For example:
      ​
      Finding the message ID from the DispatchId log
  • $GAS_AMOUNT: The amount of destination gas to pay for. We'll be paying for 550,000 gas, which is based off the overhead gas amount described here when creating a new ICA.
Using Metamask
Using cast

Getting the Interchain Gas Payment Quote

  1. 1.
    Navigate to the DefaultIsmInterchainGasPaymaster contract page on Etherscan (or its equivalent if you're sending from a non-Ethereum chain, which you could find here).
  2. 2.
    Under the Contract tab, select Read Contract.
  3. 3.
    Expand the quoteGasPayment function.
  4. 4.
    For destination domain, enter $DESTINATION_DOMAIN.
  5. 5.
    For gas amount, enter $GAS_AMOUNT, which is 550000.
  6. 6.
    Click Query and make note of the amount returned as $GAS_PAYMENT_QUOTE. For example, at the time of writing, the quote is 1 wei.

Paying the Interchain Gas Payment

  1. 1.
    Still on the DefaultIsmInterchainGasPaymaster contract page on Etherscan, select Write Contract.
  2. 2.
    Click on the Connect to Web3 button to connect your Wallet (i.e. Metamask). Make sure that you are on the correct network.
  3. 3.
    Expand the payForGas function.
  4. 4.
    For the payable amount, Etherscan expects an amount quoted in ether, while our $GAS_PAYMENT_QUOTE is in wei. To convert from wei to ether, input the amount $GAS_PAYMENT_QUOTE, which is in wei, into https://eth-converter.com/ and copy the ether amount. Use this ether amount as the payable amount.
  5. 5.
    For the message ID, input your $MESSAGE_ID.
  6. 6.
    For the destination domain, input your $DESTINATION_DOMAIN.
  7. 7.
    For gas amount, enter $GAS_AMOUNT, which is 550000.
  8. 8.
    For the refund address, input the address of the account you will sign the transaction with. This will receive a potential refund if you overpay for interchain gas.
  9. 9.
    Click "Write" and submit the transaction via your wallet/Metamask.

Getting the Interchain Gas Payment Quote

First, get a quote for how much your gas payment will cost, and save this in an environment variable called $GAS_PAYMENT_QUOTE:
cast call $IGP_ADDRESS "quoteGasPayment(uint32,uint256)" $DESTINATION_DOMAIN $GAS_AMOUNT --rpc-url $RPC_URL

Paying the Interchain Gas Payment

Now, we can call payGasFor, and we supply the gas payment quote as value in the transaction. The final parameter, $MY_ADDRESS, is the address of the account whose private key you're signing with. This address will be refunded any overpayment.
cast send $IGP_ADDRESS "payForGas(bytes32,uint32,uint256,address)" $MESSAGE_ID $DESTINATION_DOMAIN $GAS_AMOUNT $MY_ADDRESS --rpc-url $RPC_URL
--private-key $PRIVATE_KEY --value $GAS_PAYMENT_QUOTE

Confirm delivery

After the transaction that sent your call is finalized, you should be able to see a corresponding transaction delivering your message to the TestRecipient contract on the destination chain. You can watch for this transaction on Hyperlane's Message Explorer by entering the transaction hash or the sender/recipient address in the input field. You can see an example message delivery transaction here.
This transaction sent a "Hello World" message from Goerli to Alfajores
Read more under the Where is my message? section to use tools like the Hyperlane Message Debugger.​
Previous
Liquidity Layer
Next
Queries
Last modified 12d ago