A ZK-Rollup is a Layer 2 (L2) scaling solution that executes transactions off the main Ethereum chain (Layer 1) and posts compressed transaction data along with a cryptographic validity proof, known as a zero-knowledge proof (ZK-proof), to the mainnet. This proof, typically a ZK-SNARK or ZK-STARK, allows the main chain to verify the correctness of all batched transactions without re-executing them, ensuring the same security guarantees as the underlying L1. The primary goals are to drastically increase transaction throughput and reduce gas fees while inheriting the security of Ethereum.
LABS
Glossary
ZK-Rollup
A Layer 2 scaling solution that batches transactions off-chain and submits a cryptographic validity proof (ZK-SNARK/STARK) to the main chain for verification.
Chainscore © 2026
definition
BLOCKCHAIN SCALING
What is a ZK-Rollup?
A ZK-Rollup is a Layer 2 scaling solution that batches thousands of transactions off-chain and submits a cryptographic proof of their validity to the main blockchain.
The operational flow involves a network participant, often called a sequencer or operator, which collects user transactions off-chain. This operator executes these transactions and generates a new state root representing the updated ledger. Critically, it also generates a validity proof attesting that the new state root is the correct result of applying all batched transactions to the previous state. Only this compressed data bundle—containing the minimal transaction data, the new state root, and the proof—is submitted to the L1 contract, creating a massive reduction in on-chain data footprint.
ZK-Rollups offer two key security properties: validity and data availability. Validity is ensured by the cryptographic proof, making invalid state transitions impossible to commit. Data availability, the requirement that transaction data is published on-chain, allows users to reconstruct the state and exit the rollup even if the operator is malicious. This model enables trustless and fast finality; once the proof is verified on L1, the state is considered final, unlike Optimistic Rollups which have a challenge period.
Prominent implementations include zkSync Era, Starknet, and Polygon zkEVM, each with different technical approaches to proof systems and EVM compatibility. Use cases span high-frequency DeFi trading, micropayments, and gaming, where low cost and high speed are critical. The main trade-offs involve the computational intensity of proof generation, which requires specialized hardware (provers), and the current complexity of achieving full EVM equivalence in a zero-knowledge framework.
how-it-works
LAYER 2 SCALING
How ZK-Rollups Work
ZK-Rollups are a Layer 2 scaling solution that bundles thousands of transactions into a single cryptographic proof, drastically increasing blockchain throughput while inheriting the security of the underlying Layer 1.
A ZK-Rollup (Zero-Knowledge Rollup) is a blockchain scaling architecture that executes transactions off-chain and posts only a compressed data summary and a cryptographic proof of validity to the main chain. This proof, known as a ZK-SNARK or ZK-STARK, cryptographically verifies the correctness of all bundled transactions without revealing their details. By moving computation off-chain, ZK-Rollups reduce the data load on the base layer (like Ethereum), enabling significantly higher transaction throughput and lower fees while maintaining strong security guarantees derived from the underlying blockchain.
The operational flow involves two key actors: a sequencer and a prover. The sequencer batches user transactions, executes them, and generates a new state root. A prover then creates a validity proof (the ZK-proof) attesting that the state transition from the old root to the new one is correct. This compressed proof and minimal essential data (like state differences) are posted to the Layer 1. Because the proof is verified on-chain by a smart contract, the rollup's state is considered as secure as the Layer 1 itself, assuming the cryptographic primitives are sound.
A critical feature is data availability. For users to independently verify the chain's state and exit if needed, the transaction data must be accessible. In a validium, this data is stored off-chain with a committee, trading some trust assumptions for even lower costs. A standard ZK-Rollup, however, posts this data to the Layer 1 as calldata, ensuring maximum security. This design enables near-instant finality after proof verification and supports complex applications like decentralized exchanges and NFT marketplaces with minimal latency and cost.
key-features
ARCHITECTURE
Key Features of ZK-Rollups
ZK-Rollups are a Layer 2 scaling solution that bundles transactions off-chain and submits a cryptographic proof of their validity to the main chain.
01
Validity Proofs (ZK-SNARKs/STARKs)
The core cryptographic mechanism. A ZK-Rollup generates a zero-knowledge proof (like a ZK-SNARK or ZK-STARK) that cryptographically attests to the correctness of a batch of transactions. This succinct proof is verified on the Layer 1 chain, ensuring the state transition is valid without revealing the underlying transaction data.
02
On-Chain Data Availability
While computation is moved off-chain, critical transaction data (often in a compressed form) is posted to the Layer 1 chain. This ensures data availability, allowing anyone to reconstruct the rollup's state and verify the proof's claims. This is a key security distinction from validiums, which keep data off-chain.
03
Trustless Security & Finality
Security is inherited from the underlying Layer 1 (e.g., Ethereum). The validity proof is mathematically verified by the L1 smart contract. This provides cryptographic finality—once the proof is accepted, the state is final. There is no need for a fraud proof window or challenge period, unlike in Optimistic Rollups.
04
Scalability & Throughput
By moving computation and state storage off-chain, ZK-Rollups dramatically increase transaction throughput. They achieve this by:
- Batching: Thousands of transactions are proven in a single batch.
- Reduced On-Chain Footprint: Only the proof and minimal data are posted to L1.
- Parallel Execution: Transactions can be processed off-chain in parallel before proof generation.
05
Fast Withdrawals & Capital Efficiency
Because state updates are verified instantly via proofs, users can withdraw funds back to Layer 1 almost immediately after a batch is finalized. This provides capital efficiency and a better user experience compared to systems with long withdrawal delays, which are typical of fraud-proof-based designs.
06
Privacy Potential
While not all implementations use it, the zero-knowledge cryptography at the core enables enhanced privacy features. Transaction details can be hidden within the proof, allowing for selective disclosure or fully private transactions. This is a foundational difference from transparent scaling solutions.
LAYER 2 SCALING COMPARISON
ZK-Rollup vs. Optimistic Rollup
A technical comparison of the two dominant Layer 2 scaling solutions based on their core security models.
| Feature / Metric | ZK-Rollup | Optimistic Rollup |
|---|---|---|
Security Model | Cryptographic validity proofs (ZK-SNARKs/STARKs) | Economic fraud proofs with challenge periods |
Time to Finality (L1) | < 10 minutes | ~7 days (for full withdrawal) |
Transaction Throughput (TPS) | High (limited by proof generation) | High (limited by data availability) |
On-Chain Data Cost | Only proof + minimal state diff | Full transaction data (calldata) |
Trust Assumption | Trustless (cryptographic security) | Economically secure (assumes honest majority) |
Proof Generation Complexity | High computational cost (prover) | Low (sequencer only posts data) |
EVM Compatibility | Complex (ZK-EVM required) | Native (full EVM equivalence) |
Withdrawal Delay | Near-instant (after proof verification) | 1-2 week challenge period |
examples
MAJOR NETWORKS
ZK-Rollup Examples & Implementations
ZK-Rollups are not a monolithic technology but a category with distinct implementations, each with unique architectures, proving systems, and trade-offs. This section explores the leading projects.
06
Proving System Spectrum
The core cryptographic engines behind ZK-Rollups define their performance and trust assumptions.
- SNARKs (Succinct Non-Interactive Argument of Knowledge): Small proofs, fast verification. Requires a trusted setup (e.g., Groth16, PLONK). Used by zkSync, Loopring.
- STARKs (Scalable Transparent ARgument of Knowledge): Larger proofs, no trusted setup, faster prover times. Used by Starknet.
- Hybrid Systems: Combine STARKs (fast proving) and SNARKs (small final proof) for optimal performance, as seen in Polygon zkEVM.
SNARKs / STARKs
Core Tech
ZK-ROLLUP
Technical Details
Zero-Knowledge Rollups (ZK-Rollups) are a Layer 2 scaling solution that bundles transactions off-chain and submits a cryptographic proof of their validity to the main blockchain.
A ZK-Rollup is a Layer 2 scaling solution that executes transactions off-chain and then posts a single, compact cryptographic proof of their validity to the underlying Layer 1 blockchain. It works by aggregating hundreds of transactions into a batch. A Sequencer processes these transactions and generates a new state root. A Prover then creates a Zero-Knowledge Succinct Non-Interactive Argument of Knowledge (zk-SNARK) or zk-STARK proof that attests to the correctness of the state transition. Only this proof and minimal essential data (like state differences) are posted to the main chain, where a Verifier contract validates it, updating the canonical state with extreme efficiency.
security-considerations
ZK-ROLLUP
Security Model & Considerations
ZK-Rollups derive their security from cryptographic proofs and a specific data availability model. The core security guarantees and trade-offs are defined by these foundational mechanisms.
01
Validity Proofs
The primary security guarantee of a ZK-Rollup is the Zero-Knowledge Succinct Non-Interactive Argument of Knowledge (zk-SNARK) or zk-STARK. These cryptographic proofs verify that all state transitions (transactions) within a batch are valid according to the rollup's rules, without revealing the underlying data. The main chain (L1) only needs to verify this single proof to accept the entire batch, inheriting the L1's security for finality.
02
Data Availability
Security depends on the availability of transaction data. In a ZK-Rollup, this data (calldata) is posted to the L1. This allows anyone to reconstruct the rollup state and verify proofs independently. The critical security assumption is that this data remains available. Solutions like EIP-4844 (proto-danksharding) and full danksharding on Ethereum are designed to make this data availability cheaper and more scalable while maintaining security.
03
Escape Hatch (Force Withdrawal)
A critical user safety mechanism. If the sequencer becomes unresponsive or maliciously censors a user, the user can submit a fraud proof (in validity rollups, this is a proof of non-inclusion) directly to the L1 contract. This allows the user to force the withdrawal of their assets based on the latest proven state, ensuring users can always exit to L1, even if the rollup operator fails.
04
Sequencer Centralization Risk
Most ZK-Rollups currently use a single, permissioned sequencer to batch and order transactions. This creates a central point of failure for liveness (transaction inclusion) and potential censorship. The security model mitigates this via the escape hatch, but it degrades user experience. Future designs aim for decentralized sequencer sets or proof-of-stake based sequencing to reduce this trust assumption.
05
Upgradeability & Governance
Rollup smart contracts on L1 are often upgradeable by a multi-sig or DAO. This introduces a trust assumption in the upgrade key holders, who can potentially change the rollup's logic. The security model must consider the timelocks, governance processes, and transparency of these upgrades. Some rollups implement security councils or progressively decentralize control to mitigate this centralization risk.
06
Proof System Assumptions
The underlying cryptographic systems have their own security considerations:
- zk-SNARKs rely on a trusted setup (ceremony) for some systems, introducing a one-time trust assumption.
- zk-STARKs are post-quantum secure and do not require a trusted setup, but generate larger proofs.
- Both assume the underlying cryptographic primitives (hash functions, elliptic curves) are secure. A break in these could compromise the rollup's validity guarantees.
ecosystem-usage
ZK-ROLLUP
Ecosystem & Use Cases
ZK-Rollups are a leading Layer 2 scaling solution that bundles transactions off-chain and submits a cryptographic proof of their validity to the mainnet, enabling high-throughput, low-cost applications.
01
High-Throughput DeFi
ZK-Rollups enable decentralized exchanges (DEXs) and lending protocols to process thousands of transactions per second (TPS) with near-instant finality and minimal fees. This creates a user experience comparable to centralized finance while maintaining self-custody and security. Key examples include:
- dYdX: A leading perpetual futures exchange built as a ZK-Rollup.
- zkSync Era: Hosts a full ecosystem of DeFi protocols like SyncSwap and Maverick Protocol.
- Starknet: Powers DeFi applications like Ekubo and Nostra.
02
Mass Adoption Payments
By drastically reducing transaction costs to fractions of a cent, ZK-Rollups make blockchain micropayments and everyday transactions economically viable. This is critical for:
- Merchant adoption: Enabling cheap point-of-sale and e-commerce payments.
- Cross-border remittances: Providing a fast, low-cost alternative to traditional services.
- Recurring payments: Making subscriptions and payroll on-chain feasible. Projects like zkSync and Starknet are building infrastructure to support these use cases.
03
Gaming & Social Applications
The low latency and high throughput of ZK-Rollups are essential for interactive applications where user actions must be processed quickly and cheaply. This enables:
- On-chain games: Where in-game asset trades and state updates happen seamlessly.
- Fully on-chain (FOC) games and autonomous worlds: Require massive, frequent state updates.
- Decentralized social networks: Where posting, liking, and tipping are not hindered by high fees. Starknet and zkSync are prominent platforms for this emerging sector.
04
Enterprise & Institutional Solutions
ZK-Rollups provide the privacy, auditability, and scalability required for enterprise adoption. Key applications include:
- Private transactions: Using ZK-proofs to validate transactions without revealing sensitive commercial data on-chain.
- Supply chain management: Tracking goods with verifiable proofs of provenance and state changes.
- Institutional DeFi: Allowing large-scale capital deployment with reduced cost and settlement risk. StarkEx (powering dYdX and Immutable X) is a prime example of an institutional-grade ZK-Rollup engine.
05
NFTs & Digital Collectibles
ZK-Rollups make minting, trading, and transferring NFTs affordable and fast, unlocking new creative and commercial models:
- High-volume marketplaces: Enabling trading of thousands of NFTs without prohibitive gas fees.
- Gaming NFTs: Supporting dynamic in-game assets that change state frequently.
- Loyalty programs & ticketing: Using NFTs for verifiable, low-cost digital passes. Immutable X is a leading ZK-Rollup specifically optimized for NFTs and gaming assets.
06
Cross-Chain & Multi-Chain Infrastructure
ZK-Rollups are becoming key components of interoperability solutions, acting as secure, scalable hubs for asset and data transfer between chains.
- ZK-bridges: Use validity proofs to securely move assets between Layer 1 and Layer 2, or between different rollups, with strong security guarantees.
- Modular settlement layers: Some ZK-Rollups, like Polygon zkEVM, can settle proofs on multiple Layer 1s, enhancing resilience.
- Unified liquidity layers: Aggregating liquidity from various chains into a single, efficient execution environment.
ZK-ROLLUP
Common Misconceptions
Zero-Knowledge Rollups are a leading Layer 2 scaling solution, but their technical complexity often leads to widespread misunderstandings. This section clarifies the most frequent points of confusion.
No, ZK-Rollups are not inherently private for users. The "zero-knowledge" refers to the validity proof (ZK-SNARK or ZK-STARK) that cryptographically proves the correctness of state transitions without revealing all transaction data. While the proof itself is private, the transaction data (sender, receiver, amount) is typically published as calldata on Layer 1 for data availability, making it publicly visible. True privacy requires additional cryptographic layers like zk-SNARKs applied at the application level.
ZK-ROLLUP
Frequently Asked Questions
Zero-Knowledge Rollups (ZK-Rollups) are a leading Layer 2 scaling solution that bundles transactions off-chain and submits cryptographic validity proofs to the mainnet. This section answers the most common technical and practical questions about how they work, their advantages, and their ecosystem.
A ZK-Rollup is a Layer 2 scaling solution that executes transactions off-chain in batches and submits a single cryptographic proof of their validity to the underlying Layer 1 blockchain (e.g., Ethereum). It works by aggregating hundreds of transactions into a rollup block. A zk-SNARK or zk-STARK proof is generated off-chain to cryptographically verify the correctness of all state transitions (e.g., token transfers, smart contract executions) without revealing the underlying transaction data. This compressed proof and minimal essential data are then posted to the L1, where the smart contract verifies the proof and updates the canonical state root. This process drastically reduces the data and computational load on the main chain while inheriting its security guarantees.
further-reading
ZK-ROLLUP ECOSYSTEM
Further Reading
Explore the core components, leading implementations, and surrounding technologies that define the ZK-Rollup landscape.
06
Related Scaling Paradigms
ZK-Rollups exist within a broader scaling taxonomy. Key related concepts include:
- Optimistic Rollups: Assume transactions are valid and only run computation (fraud proofs) in case of a challenge. Faster finality for users, slower for fund withdrawal (e.g., Optimism, Arbitrum).
- Validiums: Use validity proofs like ZK-Rollups but store data off-chain. Higher throughput but trades off some data availability security.
- Volitions: Hybrid systems that let users choose per transaction between a ZK-Rollup (full security) and Validium (lower cost) mode.
- ZK Coprocessors: Allow smart contracts to offload complex computation to a ZK-proof-generating network and verify the result on-chain.
ENQUIRY
Get In Touch
today.
Our experts will offer a free quote and a 30min call to discuss your project.
NDA Protected
Confidentiality24h Response
Time to ValueDirectly to Engineering Team
No Sales Fluff10+
Protocols Shipped
$20M+
TVL Overall