zkSync is paving the way for a new era of scalable, secure, and developer-friendly blockchain applications by introducing highly efficient, Turing complete, and multilanguage smart contract support. Built on zero-knowledge proof (ZKP) technology, zkSync enables developers to deploy smart contracts with Ethereum-like familiarity while achieving superior performance and cost efficiency. This guide explores the core aspects of zkSync’s smart contract ecosystem, from programming models to deployment best practices.
Whether you're building decentralized finance (DeFi) protocols, NFT marketplaces, or custom dApps, zkSync offers a seamless transition path with minimal code changes. Let’s dive into the architecture and tools that make this possible.
Programming Model: Ethereum Compatibility with a ZK Twist
The smart contract programming model on zkSync is designed to mirror Ethereum’s, ensuring a smooth learning curve for developers already experienced with Solidity and Web3 frameworks.
Initially, Solidity is the primary supported language, allowing developers to use familiar constructs such as unbounded loops, recursion, dynamic arrays, and complex data structures like maps and vectors. Local variables are managed on the stack or heap, while persistent state is stored in global contract storage—just like on Ethereum.
Contracts interact through strongly typed interfaces and can access public storage fields of other contracts, enabling modular and composable designs. This compatibility means most existing Ethereum dApps can be ported with little to no modification.
👉 Discover how easy it is to start building your first zkSync smart contract today.
Composability: Seamless Contract Interactions
One of zkSync’s standout features is its full composability. Smart contracts can call each other freely across different instances, forming complex execution trees. Each transaction maintains atomicity—meaning all operations either succeed together or fail entirely—regardless of how many contracts are involved.
This capability ensures that advanced DeFi primitives like flash loans, automated market makers (AMMs), and yield aggregators function reliably in the zkRollup environment. Developers can confidently migrate protocols like Uniswap or Aave knowing that cross-contract logic will behave predictably.
With composability preserved, zkSync delivers not just scalability but also functional parity with Ethereum’s rich ecosystem.
zkEVM: The Engine Behind Scalable Execution
At the heart of zkSync’s smart contract functionality lies the zkEVM—a high-performance, Turing complete virtual machine optimized for zero-knowledge proofs.
Unlike earlier ZK systems that required custom circuits for every program, zkSync’s zkEVM uses a single, universal circuit verified via PLONK, a cutting-edge proof system known for its flexibility and auditability. This design drastically reduces development overhead and enhances security, as the circuit only needs to be audited once.
The virtual machine applies state-of-the-art bytecode optimizations and is engineered to handle high transaction loads with minimal latency. As a result, users experience near-instant finality without sacrificing decentralization or security.
Additionally, the execution trace generated by the zkEVM is SNARK-friendly, enabling efficient generation of cryptographic proofs that validate transactions off-chain before posting them to Ethereum Layer 1.
Solidity Development: Porting and Compatibility
Porting Existing Smart Contracts
Most Solidity-based DeFi and NFT projects can be deployed on zkSync with no code changes. However, there are a few important considerations:
- Cryptographic functions: In the initial version, calls to
SHA256andKeccak256are automatically replaced by the compiler with circuit-friendly hash functions. While this abstraction simplifies development, contracts relying heavily on these hashes for off-chain verification may need adjustments. - Unsupported primitives: Functions like
ecrecoverand Ethereum’s cryptographic precompiles are currently not supported due to ZK circuit limitations.
Despite these constraints, the vast majority of logic—especially business logic related to token transfers, staking, governance, and swaps—remains fully compatible.
UI Interaction: Integrating Frontends with zkSync
Developers can interact with smart contracts using standard Web3 APIs and the Ethers SDK, making frontend integration straightforward.
- For read operations, any Web3-compliant library works out of the box. Optional zkSync-specific extensions allow access to L2-only features like balance checks in alternative fee tokens.
- For write operations (e.g., sending transactions), additional logic is required due to Layer 2 nuances. For instance, zkSync supports paying gas fees in any ERC-20 token—a powerful feature that demands explicit token selection during transaction submission.
This flexibility enhances user experience but requires developers to account for fee token selection and L2-specific transaction formatting in their dApp logic.
👉 Learn how to integrate gas-efficient transactions into your dApp interface.
Submitting Transactions: Secure and Wallet-Compatible
Users sign transactions using EIP-712 messages that include a hash of the calldata. Because EIP-712 leverages native Ethereum signatures, all standard wallets—including hardware wallets like Ledger and Trezor—work seamlessly without requiring special plugins or extensions.
This ensures broad accessibility and security, maintaining trust while enabling next-generation scalability.
Deployment: Going Live on zkSync Era
The zkSync Era Mainnet is now live, offering full smart contract deployment capabilities. Developers can deploy their contracts directly using familiar tooling such as Hardhat and Foundry, with plugins available to streamline the process.
To get started:
- Visit the official zkSync Era Documentation
- Set up your development environment with zkSync plugins
- Test deployments on testnets before going live
With robust tooling and active community support, launching your project on zkSync has never been easier.
Zinc: A Deprecated Language Framework
Zinc was initially introduced as a safety-focused language for writing smart contracts and ZK circuits on zkSync. Inspired by Rust’s syntax and emphasizing formal verifiability, Zinc aimed to bridge the gap between expressiveness and security in ZKP-based development.
However, Zinc is now officially deprecated. The team at Matter Labs has shifted focus to a Solidity-first approach, recognizing that widespread adoption depends on lowering barriers for existing Ethereum developers. As a result, Zinc will receive no further updates or support.
While legacy projects may still use Zinc, new development should prioritize Solidity for long-term sustainability and ecosystem alignment.
👉 See how top developers are leveraging Solidity on next-gen ZK platforms.
Getting Help: Developer Support Resources
Stuck on a problem? You’re not alone. The zkSync community offers several resources:
- The zkEVM FAQ covers common technical questions.
- The Matter Labs Medium page provides deep dives into core concepts and updates.
- Real-time assistance is available in the zkSync Discord developer channel.
Active forums and responsive maintainers make troubleshooting fast and collaborative.
Frequently Asked Questions
Q: Can I deploy my existing Solidity contracts on zkSync without changes?
A: Yes, most Solidity contracts—especially DeFi and NFT projects—can be deployed as-is. Only those using unsupported cryptographic functions like ecrecover may require minor adjustments.
Q: Does zkSync support paying gas fees in tokens other than ETH?
A: Yes. One of zkSync’s key innovations is multi-token fee payments. Users can pay transaction fees in various ERC-20 tokens, improving usability and liquidity management.
Q: Is Zinc still recommended for new projects?
A: No. Zinc has been deprecated in favor of a Solidity-first strategy. New projects should use Solidity for better tooling support and long-term viability.
Q: Are hardware wallets compatible with zkSync?
A: Yes. Thanks to EIP-712 signing standards, Ledger, Trezor, and other hardware wallets work natively without additional configuration.
Q: What proof system does zkSync use?
A: zkSync uses PLONK, a highly efficient and upgradable proof system that allows for a single universal circuit, reducing audit complexity and improving scalability.
Q: How do I start developing on zkSync Era?
A: Begin by exploring the zkSync Era Documentation, setting up Hardhat or Foundry with zkSync plugins, and deploying to testnet environments first.
Last Updated: June 24, 2024