Explore
Glossary

Zero-Knowledge Rollup (zk-Rollup)

A zk-rollup (zero-knowledge rollup) is a Layer 2 scaling solution that bundles multiple transactions off-chain and posts a single cryptographic proof — called a zero-knowledge proof — to a Layer 1 blockchain like Ethereum. This proof validates the correctness of all transactions in the batch, enabling fast, secure, and low-cost transactions with Ethereum-level finality.

zk-rollups are a key part of Ethereum’s long-term scalability roadmap and are used by platforms like zkSync, Starknet, Polygon zkEVM, and Scroll.

How zk-Rollups Work

  • Off-Chain Execution – Transactions are processed off-chain by a zk-rollup operator or sequencer.
  • Proof Generation – A succinct cryptographic proof (e.g. SNARK or STARK) is generated to verify that all transactions are valid.
  • Proof Submission – The proof, along with minimal data, is submitted to Ethereum.
  • On-Chain Verification – Ethereum smart contracts verify the proof and update the state.
  • Instant Finality – Once the proof is verified, transactions are final and cannot be reversed.

Key Features

  • Zero-Knowledge Proofs – Proves transaction validity without revealing full transaction data.
  • High Security – Inherits Ethereum’s security while reducing data and computation on L1.
  • Fast Finality – Unlike optimistic rollups, zk-rollups finalize transactions immediately after proof verification.
  • Data Compression – Only essential data and proofs are stored on-chain, reducing gas costs.
  • Privacy Potential – zk-technology can be extended for confidential or private transactions.

Benefits of zk-Rollups

  • Scalability – Can support thousands of transactions per second while minimizing costs.
  • Lower Gas Fees – Users pay significantly less than on Ethereum mainnet.
  • Trustless Security – Finality is cryptographically guaranteed, not reliant on economic game theory.
  • Ideal for Complex dApps – zk-rollups support advanced use cases like DeFi, NFTs, and gaming at scale.
  • Final Settlement Speed – Users don’t have to wait for fraud-proof windows as in optimistic rollups.

Use Cases of zk-Rollups

  1. zkSync Era – A fully EVM-compatible zk-rollup enabling scalable DeFi and dApp development.
  2. Starknet – Uses STARKs for fast, secure computation in DeFi, gaming, and more.
  3. Polygon zkEVM – Brings zk-proof security to Ethereum-compatible smart contracts.
  4. NFT Minting at Scale – zk-rollups enable batch minting with minimal gas costs.
  5. Privacy-Preserving Apps – zk-tech can be extended for anonymous voting, private payments, or identity.
  6. Institutional Use Cases – Enterprises use zk-rollups for scalability, compliance, and data confidentiality.

Read next

Comments ()