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What is a zkEVM?

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Anatol Antonovici

Author

Anatol Antonovici

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Anatol is a crypto and Web3 writer at Cryptonews, where he creates educational articles, guides, and reviews about everything related to crypto.

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Last updated:

April 16, 2025

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A zero-knowledge Ethereum Virtual Machine, or zkEVM, is a virtual engine that can process Ethereum smart contracts and transactions using zero-knowledge proofs (ZKPs).

zkEVMs are a type of zero-knowledge (ZK) rollups, which are Layer 2 blockchains designed to scale Ethereum by executing transactions off-chain and then submitting concise ZKPs and transaction data back to the mainnet for final settlement and permanent storage.

Crypto rollups help Ethereum by increasing transaction throughput and lowering costs, but how they achieve this differs.

For years, ZK rollups were regarded as superior scaling solutions thanks to their increased security, near-instant finality, and improved privacy. However, developers faced a major challenge: integrating ZKP technology with Ethereum smart contracts was tricky, as generating proofs for arbitrary EVM operations was extremely complex and computationally intensive.

Therefore, early ZK rollups could scale simple Ethereum transactions only – not smart contracts and decentralized applications (dApps).

Thanks to recent technological advancements, zkEVMs are now a reality. They can execute Ethereum smart contracts with ZKPs. This is a game-changer, as zkEVMs combine the advanced features of ZK rollups with full dApp compatibility, taking blockchain scalability to a whole new level.

Key Takeaways

zkEVMs combine zero-knowledge proofs with Ethereum smart contract compatibility, representing a significant evolution from ZK rollups.
zkEVMs increase throughput, reduce transaction costs, and add an extra layer of privacy.
zkEVMs are an early-stage technology with only 5% market share across Layer 2s.

Understanding zkEVM

Ethereum has revolutionized blockchains by introducing the smart contract feature, which powers dApps. While it remains the go-to platform for building Web3 and decentralized finance (DeFi) applications, it still faces scalability challenges.

For example, it can handle only around 15 transactions per second (tps) – an infinitesimal amount compared to Solana’s capacity of up to 65,000. This limited throughput restricts the potential of high-volume dApps like games, payment platforms, and DeFi services.

Another problem is Ethereum’s high fees. Over the past three years, average transaction fees have frequently spiked above $1, making it inefficient for use cases like high-frequency trading.

Layer 2 solutions came to address Ethereum’s scalability issues by settling transactions off-chain. A ZK rollup is a type of Layer 2 chain that processes ETH transactions off-chain. It verifies transactions right away and then submits compact cryptographic proofs, ZKPs, back to the mainnet.

Thanks to their privacy and immediate finality, ZK rollups were considered superior to alternative scaling solutions like sidechains and optimistic rollups. However, the latter ones integrate with the Ethereum Virtual Machine (EVM) more easily due to their flexible design. On the other side, early ZK rollups couldn’t achieve smooth compatibility, preventing them from offering dApp support.

For developers, merging the EVM with ZKPs was an important task, as they could bring ZK rollups’ security, privacy, and efficiency to smart contracts. zkEVMs are the result of years of research, development, and trials.

Today, several zkEVM rollups scale Ethereum efficiently by supporting both traditional ETH transactions and smart contract operations.

L2Beat data shows that zkEVM chains have a combined total value locked (TVL) of nearly $1.8 billion, which is a small fraction of the $28 billion secured by all crypto rollups.

zkEVMs represent an essential innovation for Ethereum scalability, but they’re at an early stage.

How Does a zkEVM Work?

A zkEVM chain combines the power of ZKPs with the full functionality of the EVM. This allows Web3 developers to build and run smart contracts on a highly scalable, secure, and private Layer 2 network.

The zkEVM design has three core elements:

Execution Layer – Functions like Ethereum’s EVM, executing smart contracts and generating new states.
Proving Circuit – The prover generates ZKPs confirming the correctness of the state transitions.
Verifier Contract – Deployed on Ethereum, this smart contract receives validity proofs from the zkEVM and verifies them. It validates that the zkEVM’s state transitions are legitimate before approving them on-chain. Thanks to this verifier contract, zkEVMs inherit the security of Ethereum.

To better understand how a zkEVM works, we should dive a bit deeper into its two main components: ZKPs and the EVM.

Zero-Knowledge Proofs (ZKPs) in zkEVM

ZKP is a cryptographic method that allows one party to prove that a statement is true without revealing the information itself. In zkEVMs, this method is used to prove the validity of multiple transactions bundled together without disclosing additional details, such as wallet addresses, transaction values, balances, etc.

zkEVMs settle Ethereum transactions off-chain, sending back compact proofs only. This greatly reduces the amount of data reaching Ethereum, improving scalability and maintaining a high level of privacy.

There are two main types of ZKPs in blockchain: zk-SNARKs, from Succinct Non-Interactive Arguments of Knowledge, and zk-STARKs, short for Scalable Transparent Arguments of Knowledge.

Both types are described in more detail in our dedicated article about zero-knowledge proofs. In a nutshell, zk-SNARKs have more compact proofs and verify more quickly but require a trusted setup. Elsewhere, zk-STARKs came later, introducing larger proofs for greater scalability and transparency.

Both methods enable zkEVMs to bundle thousands of transactions into a single proof, which is eventually recorded on Ethereum for final settlement.

zk-Rollups vs. Traditional Layer 2 Scaling Solutions

Before moving to the EVM component, it’s important to understand that ZK rollups greatly differ from optimistic rollups, which currently account for more than 80% of the total value held on all crypto rollups.

While optimistic rollups treat all transactions as valid unless disputed during a challenge period of seven days, ZK rollups verify each transaction in every batch using ZKPs and send proofs to Ethereum. This allows ZK rollups to reach faster finality and offer better security.

Therefore, ZK rollups offer a more efficient and safer method for scaling Ethereum transactions.

Compatibility with Ethereum and Smart Contracts

The innovation of zkEVM refers to its compatibility with the EVM – Ethereum’s virtual computer that runs all smart contracts. Thanks to EVM support, developers can deploy Ethereum smart contracts on Layer 2 rollups without rewriting them. They can use the same tools and libraries to migrate dApps to a zkEVM.

Developers can also write zkEVM smart contracts from scratch using Solidity, the programming language created for Ethereum. These rollups replicate the logic of the EVM, but they use ZKPs for scaling and security. Everything on zkEVMs works faster and cheaper compared to Ethereum.

More importantly, besides serving as a migration-friendly platform, a zkEVM can scale existing smart contracts hosted by Ethereum. Instead of scaling simple ETH transactions, like the first generation of ZK rollups, zkEVMs bundle Ethereum smart contract transactions off-chain as well, submitting the compressed proof to the mainnet.

Thanks to its EVM compatibility, a zkEVM offers the same flexibility as popular optimistic rollups but with near-instant finality and enhanced privacy.

Key Features of zkEVM

zkEVMs are a mix of zero-knowledge cryptography and Ethereum compatibility. This symbiosis helps dApps become faster, cheaper, and more secure, contributing to accelerated Web3 adoption.

Let’s explore the main features that make zkEVM a powerful upgrade for the Ethereum ecosystem.

Scalability and Gas Fee Reduction

The main goal of a crypto rollup is to scale Ethereum by offering increased throughput and lower prices.

As mentioned earlier, zkEVMs process Ethereum transactions off-chain by bundling them into batches. In this way, these Layer 2 chains reduce the load on Ethereum, as each batch containing multiple transactions is verified with a single proof. That’s way faster than verifying each transaction individually.

In addition to speeding up processing, this rolling-up approach reduces gas fees for end users, making it more affordable to use dApps. Following Ethereum’s Dencun upgrade in March 2024, the transaction costs on all crypto rollups, including zkEVMs, were reduced by over 80%.

zkSync Era and Scroll, some of the largest zkEVMs by TVL, saw the most significant declines in transaction fees, which fell more than 94% since before the Dencun implementation.

Thanks to these features, zkEVMs are able to support high-volume apps like gaming and DeFi trading platforms.

Security and Decentralization

By submitting ZKPs to Ethereum verifier contracts, zkEVMs inherit the security of Ethereum, which is powered by thousands of nodes dispersed all over the world validating transactions and state changes.

This trustless verification model aligns with the decentralized nature of Ethereum, reducing the risk of fraud.

Once zkEVM proofs are validated on Ethereum, the information is stored permanently and cannot be changed.

Privacy Enhancements

Another major feature that sets ZK rollups apart from other scaling networks is privacy. Thanks to zero-knowledge proofs, zkEVMs can settle transactions without revealing additional details, such as wallet addresses.

Meanwhile, zkEVMs align with Ethereum’s transparency, ensuring that transactions are provable and auditable without revealing unnecessary details.

In April 2025, Ethereum co-founder Vitalik Buterin reiterated his support for privacy in blockchain, stressing that it was an important guarantor of decentralization.

“Whoever has the information has the power, ergo we need to avoid centralized control over information,” he said.

Buterin praised the efficiency of zk-SNARKs, which can protect our identities while demonstrating our trustworthiness.

Types of zkEVMs

All zkEVMs operate using the same core principles, but they differ based on their level of compatibility with Ethereum. It turns out that higher compatibility is achieved at the expense of performance, and this happens because Ethereum wasn’t originally designed with zero-knowledge technology in mind.

In 2022, Vitalik Buterin shared a post discussing four main types of zkEVMs.

Here is how they differ:

Type 1: Fully EVM-Equivalent

These zkEVMs are fully compatible with Ethereum, maintaining all its functionalities. This close replication enables them to communicate with Ethereum dApps and reuse block explorers and execution clients.

However, one major trade-off is that Type 1 zkEVMs deal with the longest proving times due to the difficulty of mimicking the entire Ethereum network. Taiko is a good example of this type of zkEVM.

Type 2: Near EVM-Equivalent

Type 2 zkEVMs also aim to be fully compatible with the EVM, but they make some modifications to achieve better performance. For example, they remove parts of the Ethereum stack that require complex and ZK-unfriendly cryptography. zkEVMs implementing these changes can offer faster prover times.

Examples of Layer 2s falling under this category are Scroll, Linea, and Polygon zkEVM. The majority of existing smart contracts, developer tools, and wallets work seamlessly with these chains. This means that developers don’t have to make changes to their code when migrating to Scroll or Polygon zkEVM, eliminating the possibility of new security risks and the need for extra audits.

Buterin also recognizes Type 2.5 zkEVMs, which make similar changes to the EVM but increase gas costs for certain operations to speed up the proving times.

Type 3: Almost EVM-Equivalent

This type of zkEVM sacrifices some EVM compatibility to further speed up proof generation. They remove some ZK-unfriendly features, like precompiles, and make changes to VM memory, the stack, and how smart contract code is treated. For more details about how the EVM memory, stack, and bytecodes work, read our dedicated article about the EVM.

While most Ethereum dApps will function in this environment, some may require major modifications.

This is regarded as a transition stage for zkEVMs until they add precompiles and become Type 2 or 2.5.

Type 4: High-Level-Language Equivalent

Finally, Type 4 zkEVMs are compatible with Ethereum’s programming languages, like Solidity and Vyper, but they are less interoperable with the EVM itself. These zkEVMs can take code written in Solidity and compile it to a ZK-friendly format. In this way, they achieve the fastest proving times, but contracts may not have the same addresses and many Ethereum dApps may not work on these networks.

Type 4 zkEVMs can address specific use cases, such as gaming or trading. For example, Immutable X is an optimized game-specific ZK rollup.

General purpose Type 4 zkEVMs include zkSync Era and Starknet.

Interestingly, Type 4 zkEVMs like zkSync Era and Starknet have the highest TVL figures as per L2Beat, which demonstrates that the crypto community prioritizes performance.

However, in DeFi, Type 1 and Type 2 zkEVM dominate, as the sector requires scaling solutions that have seamless communication with Ethereum dApps.

Benefits of zkEVM

zkEVMs have several major benefits compared to Ethereum and other types of Layer 2s:

Scalability – The main goal of any crypto rollup is to scale the underlying chain, and zkEVMs do a great job at boosting Ethereum’s transaction throughput. By processing transactions outside Ethereum, zkEVMs can handle hundreds and even thousands of transactions per second.
Lower gas fees – zkEVMs submit a single proof to validate larger batches comprising multiple transactions. This greatly reduces gas costs, making dApps and Layer 2 transactions affordable and efficient. The average transaction fee on zkEVMs is from 10 to 20 times lower than on Ethereum.
Finality – Unlike optimistic rollups, which impose a 7-day challenge period before transactions are finalized, zkEVMs use ZKPs to verify each transaction upfront, achieving near-instant finality.
Integration with Ethereum dApps – Unlike typical ZK rollups, zkEVM integrate with Ethereum dApps by replicating the EVM either fully or partially. Developers can easily move Ethereum dApps to zkEVM ecosystems.
Enhanced privacy – By generating zero-knowledge proofs for all transactions, zkEVMs offer a privacy layer that is not possible in optimistic rollups or other scaling solutions.
Network effects – Developers can easily build dApps on zkEVM by leveraging the existing Ethereum ecosystem. For example, they can use code libraries, tooling, and documentation, benefiting from existing work that took years of development.

Limitations of zkEVM

There is a reason why zkEVMs have a small share of the Layer 2 market, and this has to do with several limitations that prevent these from dominating Ethereum scaling. Here is what zkEVMs have to improve:

Complexity of implementation – The EVM was never intended to support zero-knowledge computation, which makes the development and implementation of zkEVMs quite difficult. For example, zkEVM creators have to address several technical complexities of the EVM, including adjusting to its stack-based architecture, opcodes, and storage overhead.
Computational costs of generating ZKPs – While zkEVM transactions are cheap, generating ZKPs is a resource-intensive process that requires expensive hardware.
Lower compatibility – The goal of zkEVMs is to be interoperable with Ethereum smart contracts, but they’re still less compatible with the EVM compared to most optimistic rollups or sidechains.

Despite these challenges, zkEVMs have experienced ongoing improvements to enhance efficiency. For example, more powerful GPUs and specialized ASIC hardware could generate ZKPs much faster.

zkEVM vs. Other Scaling Solutions

zkEVMs represent a breakthrough in blockchain scaling, but they still have to achieve the same user experience level as their competitors like optimistic rollups or sidechains. Let’s see where zkEVMs stand compared to scaling alternatives:

zkEVM vs. Optimistic Rollups

As mentioned earlier, both zkEVMs and optimistic rollups scale Ethereum by processing transactions off-chain and settling proofs on the mainnet. However, the latter ones treat all transactions as valid and allow everyone to submit fraud proofs during a 7-day challenge period.

On the other side, zkEVMs use zero-knowledge proofs to verify all transactions right away, submitting a validity proof to Ethereum for each batch of transactions.

Therefore, zkEVMs achieve faster finality, although they require specialized hardware to generate ZKPs.

Despite enhanced security, privacy, and faster finality, zkEVMs still have a smaller market share compared to optimistic rollups. This is because optimistic rollups are easier to integrate with dApps and provide a better user experience.

As per L2Beat data from mid-April 2025, ZK rollups, most of which are zkEVMs, have a TVL of $1.77 billion, accounting for only 5% of the TVL across all Ethereum Layer 2s. Optimistic rollups dominate the market with a market share of nearly 80%.

However, zkEVMs are still at an early stage. Buterin expects ZK rollups to dominate the Ethereum scaling ecosystem within a decade. He anticipates that all rollups will use ZKPs, although it takes a lot of infrastructure to get there.

zkEVM vs. Sidechains

Sidechains like Polygon PoS are separate, smaller blockchains that run in parallel to Ethereum, although they are powered by their own consensus mechanisms. Given their smaller sizes and fewer validating nodes, sidechains may offer high throughput and low fees, but they don’t inherit Ethereum’s security. The sidechain architecture and approach raise centralization and security concerns.

zkEVMs are built as Layer 2 rollups, benefiting from Ethereum’s security and decentralization. This model ensures that users don’t have to rely on a separate validator network or centralized bridges.

While sidechains may be faster or cheaper in the short term, zkEVMs offer a stronger long-term solution by offering both scalability and Ethereum-grade security.

Some blockchain projects, such as Polygon, offer both types of scaling solutions. Polygon PoS, a sidechain run by over 100 validators, has a TVL of over $2.7 billion, and Polygon zkEVM has only about $30 million in TVL.

Conclusion

zkEVMs are a major breakthrough in blockchain, as they mix the security of Ethereum, the interoperability of the EVM, and the efficiency of ZK rollups. This combo enables zkEVMs to offer faster, cheaper, and more private transactions while supporting dApps.

ZK rollups have shown promising scaling results, but they couldn’t integrate with smart contracts. zkEVMs can read Solidity code and handle dApp operations, offering a superior Web3 experience.

Although they’re still at an early stage of adoption, zkEVMs are gaining momentum across multiple use cases, especially gaming and identity.

Ethereum scaling platform Immutable X is merging into Immutable zkEVM, reflecting the benefits of the zkEVM technology. Another gaming-oriented project adopting the model is Ronin, which is preparing to launch Ronin zkEVM later in 2025.

As ZK technology matures, blockchain experts anticipate zkEVMs to play a major role in Ethereum’s long-term future. For example, Vitalik Buterin sees ZK rollups dominating Layer 2s in the coming years.

The balance they strike between decentralization, performance, and security means that zkEVMs are likely to play a key role in blockchain technology for years to come.