Send Cross Chain Message from Hedera to Avalanche Testnets Using LayerZero

This repository shows how to use LayerZero with Hedera. It specifically demonstrates how to send a message between Hedera and Avalanche testnets using LayerZero's OApp (Omnichain Application) Standard.

LayerZero's OApp enables communication between smart contracts across different blockchains. It provides developers with a standard message-passing interface, which lets applications like DeFi protocols, DAOs, or NFTs interact cross-chain. Through OApp, a contract on one chain can send data or instructions to another chain. For more details on OApp, see the References section.

Try It in Gitpod

1a. Add Hedera Testnet to MetaMask	1b. Add Avalanche Testnet to MetaMask
2a. Get testnet HBAR from the Hedera Faucet: https://portal.hedera.com/faucet	2b. Get testnet AVAX from this faucet (Select Avalanche Fuji): https://faucets.chain.link/

3. Enter your testnet credentials in the .env file. Never share your private keys publicly. Do not commit your .env file to a public repository.

   PRIVATE_KEY=
   

4. Deploy the contracts to both chains:

   npx hardhat lz:deploy

   You should see:

   

   Upon successful deployment, you should see output like the following:

   Network: avalanche-testnet
   Deployer: 0x88cE2A88D4cdBC2b42D45748eC36103d6875dA91
   Network: hedera-testnet
   Deployer: 0x88cE2A88D4cdBC2b42D45748eC36103d6875dA91
   Deployed contract: MyOApp, network: avalanche-testnet, address: 0x6f5FeD9e63c0fAB53e2Ba1E0e76cA8C62A45758b
   Deployed contract: MyOApp, network: hedera-testnet, address: 0x6f5FeD9e63c0fAB53e2Ba1E0e76cA8C62A45758b
   

5. Copy the deployed contract addresses to the .env file

   MY_OAPP_HEDERA_CONTRACT_ADDRESS=0x6f5FeD9e63c0fAB53e2Ba1E0e76cA8C62A45758b
   

6. Initialize the OApp configuration (ex Hedera Testnet -> Avalanche Fuji path set in ./layerzero.config.ts. Learn how to set custom config paths here):

   npx hardhat lz:oapp:config:init --contract-name MyOApp --oapp-config layerzero.config.ts

   Select the relevant networks from the list for the OApp configuration.

7. Wire the OApp:

   npx hardhat lz:oapp:wire --oapp-config layerzero.config.ts

   Confirm Y to proceed with the preview and sign the transaction.

8. Move the test file to the deploy folder and run the test to send a message between chains:

   mv sendAcrossChainsLz.ts deploy/
   npx hardhat run ./deploy/sendAcrossChainsLz.ts

   You should see output like the following:

   Contract address: 0x6f5FeD9e63c0fAB53e2Ba1E0e76cA8C62A45758b
   Wallet address: 0x88cE2A88D4cdBC2b42D45748eC36103d6875dA91
   
   Test case 1:
   Parameters: { dstEid: 40106, message: 'Hello from Hedera!', payInLzToken: false }
   Quoted fee - Native Fee: 269469144 HBAR, LZ Token Fee: 0
   Adjusted Native Fee: 2.69469144 HBAR
   Estimated gas: 0.000000000000231397
   Transaction hash: 0xd90758d94ce3614048d04332427d49d60aa114cd7d520c4c0b5fb16c64c9d45c
   Transaction confirmed in block: 11378066
   

9. With the transaction hash from the previous step, you can view the transaction on the LayerZero, Hedera, and Avalanche explorers.

   	LayerZero	Hedera	Avalanche
   Explorer URL	https://testnet.layerzero.network/explorer/avalanche-testnet/0xd90758d94ce3614048d04332427d49d60aa114cd7d520c4c0b5fb16c64c9d45c	https://hashscan.io/testnet/tx/0xd90758d94ce3614048d04332427d49d60aa114cd7d520c4c0b5fb16c64c9d45c	https://testnet.snowtrace.io/tx/0xc9652809c2af37de078f47a7aefd7c7b8a88d2608ba1d418ddbf6ea8eb3d360b
   Transaction View

Local Setup

1. Clone the repository

   git clone https://github.com/ed-marquez/hedera-example-layer-zero-bridging-oapp.git

2. Copy .env.sample to .env and add your environment variables (and Hedera testnet credentials)

   cp .env.sample .env

3. Install dependencies with pnpm (recommended)

   pnpm install

4. Follow steps 1-9 in the Try It in Gitpod section to deploy the contracts and send a message between chains.

References

• Create LZ OApp Quickstart
• LayerZero V2 OApp Quickstart