​
Prerequisites​

  • Hyperlane CLI: Make sure you have the latest version of the Hyperlane CLI installed. 
    npm install -g @hyperlane-xyz/cli
  • Anvil (foundry): Installed to run local chains. Install it via 
    curl -L https://foundry.paradigm.xyz | bash
  • Node.js (v18 or later)
  • Deployer Wallet Private Key: You need a funded wallet for deploying contracts. This will be used as the HYP_KEY. 
    export HYP_KEY=<YOUR_PRIVATE_KEY>

​
Step-by-Step Guide​

​
1. Environment Setup

Create a working directory for the Hyperlane configuration:​ 
mkdir hyperlane-local-test && cd hyperlane-local-test

​
2. Start Two Distinct Anvil Nodes​

We will run two Anvil nodes with unique chain IDs.
  • On a first terminal, start the first Anvil node: 
    anvil --port 8545 --chain-id 31337 --block-time 1
    • Runs on http://localhost:8545.
    • Chain ID: 31337.
  • In a new terminal, start the second Anvil node: 
    anvil --port 8546 --chain-id 31338 --block-time 1
    • Runs on http://localhost:8546.
    • Chain ID: 31338.

​
3. Initialize the Hyperlane Registry​

On a new terminal, use the Hyperlane CLI to create configurations for both Anvil nodes: 
hyperlane registry init
Follow the prompts to set up anvilnode1. The CLI will ask you for the details of your chains including chainId and RPC URLs. Repeat the process for anvilnode2. This process will create metadata.yaml files under $HOME/.hyperlane/chains/anvilnode1 and $HOME/.hyperlane/chains/anvilnode2. Example metadata:
  • anvilnode1
chainId: 31337displayName: Anvilnode1domainId: 31337isTestnet: truename: anvilnode1nativeToken:  decimals: 18  name: ETH  symbol: ETHprotocol: ethereumrpcUrls:  - http: http://localhost:8545
  • anvilnode2
chainId: 31338displayName: Anvilnode2domainId: 31338isTestnet: truename: anvilnode2nativeToken:  decimals: 18  name: ETH  symbol: ETHprotocol: ethereumrpcUrls:  - http: http://localhost:8546

​
4. Deploy Core Contracts​

We’ll configure and deploy Hyperlane core contracts.
You’ll need the deployer wallet private key to deploy the core contracts. You can use export HYP_KEY='<YOUR_PRIVATE_KEY>' to set the private key as an environment variable.
hyperlane core init
The deployment configuration will be saved to ./configs/core-config.yaml. Next, deploy the core contracts: 
hyperlane core deploy
Follow the prompts to select anvilnode1. The CLI will deploy Mailbox, Interchain Security Modules (ISMs), and other required contracts. Repeat the process for anvilnode2. Once complete, you’ll find addresses.yaml in $HOME/.hyperlane/chains/anvilnode1 and $HOME/.hyperlane/chains/anvilnode2, with the deployed contract addresses.
You should be able to see the messages of the contract deployments on your terminals running the local nodes.

​
5. Send a Test Message​

Use the Hyperlane CLI to send a message from anvilnode1 to anvilnode2. 
hyperlane send message --relay
The CLI will prompt you to provide the origin chain (anvilnode1) and the destination chain (anvilnode2).
For local testing, the --relay flag automatically relays the message to the destination chain.
After sending the message, check the following:
  • Validator Logs: Look for entries indicating that signatures were generated and stored.
  • Relayer Logs: Look for successful metadata retrieval and message processing.
  • Anvil Logs: Ensure blocks were mined to process the transactions.
🎉 You’ve sent a message between two local Anvil nodes using Hyperlane!

​
Troubleshooting​

  1. “Could not fetch metadata” warning:
    • Reason: This occurs when the relayer cannot retrieve validator signatures required to process a message. Common causes:
      • The validator key lacks testnet funds.
      • The validator has not announced its storage locations.
    • Solution:
      • Ensure the validators have announced their storage locations. Check validator logs for a message such as: Validator has announced signature storage location, locations: ["file:///tmp/hyperlane-validator-signatures-local"].
      • Verify that each validator has a unique signature storage path (--checkpointSyncer.path) to prevent overwriting.
      • Confirm that the relayer has read access to the storage paths.
  2. Messages time out:
    • Reason: Anvil doesn’t auto-mine blocks by default, causing validators or relayers to wait indefinitely for new blocks.
    • Solution: Make sure to use the --block-time 1 flag when starting Anvil to auto-mine blocks every second.
  3. Validator mismatch or misconfiguration:
    • Reason: The ISM configuration on the destination chain does not match the validator key(s) used by the origin chain.
    • Solution: Check that the ISM configuration includes the correct validator addresses. Validator logs can help identify the announced addresses.