Overview
Axelar is a platform designed to facilitate secure cross-chain communication for Web3, enabling the development of interchain decentralized applications (dApps) that can operate beyond a single blockchain. Built on a proof-of-stake model, Axelar provides a secure means for developers to interact with smart contracts across different chains using Solidity or JavaScript. The platform’s core functionality includes the ability to send fungible tokens securely between many Cosmos and Ethereum Virtual Machine (EVM) chains, as well as other complex transfers. Additionally, Axelar supports General Message Passing, which allows for calling smart contract functions across blockchains.
Architecture and Functionality
Axelar’s architecture is centered around gateway smart contracts, validators, and relayer services. Gateway smart contracts enable Axelar to communicate messages across all connected chains. Each EVM chain connected to the Axelar network has a Gateway contract deployed to it, which is used to pass messages from the Axelar network to the connected chain. The Gateway contract is controlled by a key, which is held jointly by all the Axelar validators through a multi-party cryptography scheme.
Validators in the Axelar network play two main roles. First, they participate in consensus on the Axelar network, producing blocks and validating transactions as with other proof-of-stake chains. Beyond this, Axelar validators also have additional duties as they are responsible for verifying all cross-chain activity being processed by the network. This requires validators to run nodes for Axelar-supported chains, and observe those external chains for activity.
Relayer services are a type of optional convenience services provided by Axelar. These are tasks that can be performed by anyone, and no form of trust is required to authorize or complete the task. These tasks are still important however, as they must be done by someone to enable successful cross-chain communication.
Developer Tools and Resources
Axelar provides several tools to make building interchain dApps simpler. These include a curated collection of interchain examples using Axelar that can be executed locally or deployed to testnets, and the Axelar JavaScript SDK. Developers can also create locally simulated chains with RPC endpoints on localhost, deploy custom IAxelarExecutable contracts to simulated EVM chains, and test their dApp against the RPC endpoints and contract addresses of their local development environment.
