What Is Rollup Technology?

Rollup Technology is a Layer 2 scaling solution that executes transactions off of the main chain (Layer 1) but posts the transaction data back to the Layer 1 chain. This process "rolls up" hundreds of transactions into a single batch and uses cryptographic proofs to guarantee the correctness of the execution, offering massive increases in throughput and reduced transaction fees.

Go Back
Blog Thumbnail

🕒 7:29 AM

📅 Oct 27, 2025

✍️ By Nathanael707

Defining Rollup Architecture
Rollups are the leading solution for scaling the transaction throughput of decentralized blockchains like Ethereum. They execute the vast majority of transactions off-chain, significantly reducing fees and increasing speed. Crucially, they use the security of the Layer 1 chain for finality and data availability.

Layer 2: The execution environment where transactions occur cheaply and quickly.

Data Posting: All transaction data is compressed and posted back to the Layer 1 chain.

Security Inheritance: Rollups inherit the security and finality guarantees of the underlying Layer 1 blockchain.

The Two Types of Rollups
Rollups are categorized by the cryptographic method they use to prove the correctness of the off-chain execution.

Optimistic Rollups (ORs): Assume all transactions are valid by default ("optimistically"). They use a fraud proof system, allowing a challenge period (typically 7 days) where anyone can prove a transaction was fraudulent.

ZK-Rollups (ZKs): Use Zero-Knowledge Proofs to cryptographically prove that all transactions in the rolled-up batch are valid. This offers instant, cryptographic certainty without a challenge period.

Benefits and Trade-offs
Rollups are a fundamental breakthrough, allowing a high degree of scaling while preserving the core security of the main chain.

Massive Throughput: Can process thousands of transactions per second (TPS).

Low Cost: Costs are dramatically reduced by spreading the Layer 1 gas fee across hundreds of transactions.

Security: Users do not need to trust the Layer 2 operator, only the cryptography and the Layer 1 chain.

Withdrawal Speed: ORs have a 7-day withdrawal delay; ZK-Rollups offer near-instant withdrawals.