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Layer Zero

LayerZero is a messaging protocol, not a blockchain. Using smart contracts deployed on each chain, in combination with Decentralized Verifier Networks (DVNs) and Executors, LayerZero enables different blockchains to seamlessly interact with one another.

Getting Started​

To start sending omnichain messages with LayerZero, you only need to implement two functions:

  • _lzSend: This function is used to send a message to a different chain.
_lzSend(
  _dstEid, // the destination endpoint id
  _payload, // encoded message payload being sent
  _options, // message execution options
  MessagingFee(msg.value, 0), // the fee in native gas and ZRO token
  payable(msg.sender) // refund address in case of failed source message
);
  • _lzReceive: This function is used to receive a message from a different chain.
function _lzReceive(
  Origin calldata _origin, // struct containing srcEid, sender address, and the message nonce
  bytes32 _guid, // global message packet identifier
  bytes calldata payload, // encoded message being received
  address _executor, // the address of who executed the message
  bytes calldata _extraData // appended executor data for the call
) internal override {
  data = abi.decode(payload, (string)); // your receive logic here
}

LayerZero offers Contract Standards that simplify this implementation by providing out of the box message handling, interfaces for custom protocol configurations, and other quality of life improvements:

  • OApp: the base contract standard for omnichain messaging and configuration.

  • OFT: the base contract standard for omnichain messaging and configuration.

Prerequisites​

  1. You should first be familiar with writing and deploying contracts to your desired blockchains. This involves understanding the specific smart contract language and the deployment process for those chains.
  2. A wallet set up and funded for the chains you'll be working with.

Deploying your Contracts​

note

This example can be used with any EVM compatible chain.

To learn how to deploy your contracts, please refer to the Deploying Contracts section.

To checkout endpoint addresses please refer to the Endpoints section in the layerzero docs.

Connecting your Contracts​

To connect your contracts, call setPeer and pass the address of your destination contract as a bytes32 value, as well as the destination endpoint ID. If successful, you now should be setup to start sending cross-chain messages!

To go more in depth, please refer to the Getting Started section in the layerzero docs.