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What is a layer 1?
A layer 1 is a base blockchain, such as Bitcoin or Ethereum, that records and settles transactions itself. It has its own network of nodes, its own block producers and its own consensus mechanism — the rules nodes use to agree on the history.
What it means for you
Fees and confirmation times on a layer 1 are set by that chain alone, and a payment it settles cannot be reversed by any company. Coins on different layer 1s are separate: bitcoin cannot be sent to an Ethereum address, and moving value between them needs a bridge or an exchange.
How it works
ethereum.org lists what a layer 1 such as Ethereum supplies: node operators who secure and validate the network, block producers, the chain itself with its transaction history, and the consensus mechanism. Its capacity is limited, roughly 15 transactions per second on Ethereum mainnet, so busy periods push fees up. Layer 2 networks build on top and settle to it: Ethereum then serves as their data-availability layer, and once a rollup's data is on layer 1, reverting a rollup transaction would require reverting Ethereum.
Source: ethereum.org: Layer 2 (Layer 1 vs Layer 2) · checked 4 October 2026
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