Smart contracts in zkSync operate similarly to those on Ethereum but with enhanced scalability and efficiency due to the underlying zkRollup technology. zkSync uses zero-knowledge proofs to maintain security and trustlessness while processing transactions off-chain.

Zero-knowledge succinct non-interactive arguments of knowledge (zk-SNARKs) are used to verify the correctness of computations off-chain. In zkSync, zk-SNARKs ensure that all transactions and smart contract executions are valid without having to perform the computations on the Ethereum mainnet. This reduces the computational load and associated gas fees, enabling higher throughput.

zkSync Era, the latest iteration, is fully compatible with the Ethereum Virtual Machine (EVM). This means that most smart contracts written for Ethereum can be deployed on zkSync with little to no modification. The EVM compatibility ensures that developers can use familiar tools and languages (such as Solidity) to write and deploy their contracts.

zkSync Era also integrates zkPorter, a data availability solution that enhances scalability. zkPorter allows certain data to be kept off-chain, significantly increasing the number of transactions that can be processed without congesting the Ethereum mainnet.

Writing and Deploying Smart Contracts

Smart contracts for zkSync are written in Solidity, the same language used for Ethereum smart contracts. Developers can use the same syntax and logic structures they are accustomed to, making the transition to zkSync very straightforward.

Deploying Smart Contracts

1.Set Up Development Environment:

• Install Node.js and npm (Node Package Manager).
• Install the zkSync and hardhat packages via npm.
• Initialize a new Hardhat project and configure it to work with zkSync.

2.Configuration:

Modify the hardhat.config.js file to include zkSync-specific settings, such as the zkSync network URLs and zkSync-specific compiler options.

Example configuration might look like:

3.Compile the Smart Contracts:

Using the Hardhat framework, it is possible to compile Solidity contracts. The Hardhat zkSync plugin ensures that the compilation is compatible with the zkSync network.

4.Deploying Smart Contracts:

The deployment process involves connecting to the zkSync provider, creating a wallet instance, and using it to deploy the contract. Example deployment script:

Development Tools Available

Hardhat

Hardhat is a development environment and task runner for Ethereum that has been extended to support zkSync. It allows developers to compile, deploy, test, and debug Solidity smart contracts.

zkSync SDK

The zkSync SDK provides tools and libraries to interact with zkSync from a JavaScript environment. It includes utilities for setting up wallets, sending transactions, and interacting with smart contracts deployed on zkSync.

zkSync CLI

The zkSync command-line interface (CLI) offers functionalities to manage zkSync projects, including deploying contracts and managing accounts.

Remix IDE

Remix is an open-source web and desktop application that helps write Solidity contracts straight from the browser. It supports zkSync through plugins and configurations that connect it to the zkSync network.

Integration

The development tools integrate to provide a cohesive environment for developing, testing, and deploying smart contracts on zkSync.

Hardhat and zkSync SDK

Hardhat integrates with the zkSync SDK to provide a smooth workflow for developers. Hardhat plugins for zkSync handle the compilation and deployment processes, while the zkSync SDK provides the underlying functionality to interact with the zkSync network. This combination allows developers to write deployment scripts and tests using familiar Hardhat constructs while leveraging zkSync-specific features.

Hardhat and Remix

Developers can write and test smart contracts using Remix and then use Hardhat for more complex deployment scenarios. The compiled artifacts from Remix can be easily imported into a Hardhat project, allowing for flexible development workflows.

zkSync CLI

The zkSync CLI can be used alongside Hardhat and the zkSync SDK to manage deployments and interact with deployed contracts. It provides a command-line interface for common tasks, such as deploying contracts or managing account keys, which can be integrated into automated deployment pipelines.

Testing and Debugging

Hardhat’s testing framework can be used to write unit and integration tests for smart contracts. These tests can run on a local zkSync node or a testnet to ensure that contracts behave as expected. The zkSync SDK facilitates interaction with the contracts during testing, allowing for comprehensive test coverage.

By integrating these tools, developers can efficiently write, test, deploy, and manage smart contracts on zkSync, using the scalability and cost-efficiency of zkRollups while maintaining a familiar development experience. This integration supports a strong development lifecycle, from initial contract creation through deployment and ongoing maintenance.

Highlights

• Writing and deploying smart contracts on zkSync involves using Solidity and Vyper, with compilation through custom zkSync compilers.
• The zkSync CLI and SDK provide comprehensive tools for project setup, contract compilation, deployment, and interaction.
• Integration with development tools like Hardhat, Foundry, Remix, and Atlas enhances the developer experience.
• Adhering to best practices ensures secure and efficient smart contract development on zkSync.