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Layer 2

TechTerm

A Layer 2 (or L2) is a protocol built on top of a main blockchain (Layer 1, such as Ethereum) to process transactions faster and more cheaply, while inheriting the security of the L1.

A Layer 2 (or L2) is a protocol built on top of a main blockchain (Layer 1, such as Ethereum) to process transactions faster and more cheaply, while inheriting the security of the L1.

The main L2 types on Ethereum are rollups: optimistic rollups (Optimism, Arbitrum, Base) and zk-rollups (zkSync, Starknet, Linea, Polygon zkEVM), which aggregate thousands of transactions off-chain and then publish a compact proof to the L1.

L2s have become the default environment for DeFi and most decentralised applications in 2026, with direct on-chain activity on Ethereum itself now in the minority.

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