Definition
The base blockchain protocol itself — the foundational network layer. Bitcoin and Ethereum are Layer 1 blockchains. All other protocols built on top of them (like rollups) are Layer 2.
Why It Matters
Layer 1 is the foundation of security and decentralization. Understanding the difference between L1 and L2 helps you evaluate where your assets actually live and the risks involved.
Example
Ethereum is a Layer 1 blockchain. Transactions settled directly on Ethereum are finalized on the base layer — the most secure and decentralized form of settlement.
Related Terms
Layer 2
Blockchain
Ethereum
Bitcoin