Layer 2
A Layer 2 is a secondary network or protocol built on top of a blockchain to process transactions faster and cheaper while relying on the main chain for security.
Layer 2 refers to a scaling system built on top of a base blockchain, often called Layer 1, such as Ethereum or Bitcoin. Instead of having every transaction fully processed on the main chain, a Layer 2 handles activity off the base layer or in a more efficient environment, then periodically records proofs or summaries back to the main blockchain. This helps reduce congestion and fees while still using the underlying chain as a source of security and final settlement.
Layer 2 networks matter because popular blockchains can become slow or expensive when many people use them at once. They are commonly used for payments, token swaps, games, and apps that need lower costs or faster confirmation times. A practical comparison is a busy highway: the Layer 1 is the main road, while a Layer 2 is an express lane that moves many vehicles efficiently and later reconnects to the main road. Examples include rollups on Ethereum and the Lightning Network for Bitcoin.
Other terms in Layer 2 & Scaling
Data Availability
The assurance that the transaction data needed to verify a blockchain or layer 2 network can be accessed by anyone who needs it.
Fraud Proof
A fraud proof is evidence submitted to a blockchain to show that a proposed transaction result or rollup state is invalid.
Layer 3
A Layer 3 is an application-specific blockchain layer built on top of a Layer 2 to add customization, scalability, or specialized features.
Modular Blockchain
A blockchain design that splits core jobs like execution, settlement, consensus, and data availability across separate specialized layers.