CashboardGlossary · Onchain
What is a layer 2?
A layer 2 is a chain that runs transactions on its own and settles them to a base chain such as Ethereum, borrowing most of that chain's security.
How does a layer 2 work?
L2s exist because Ethereum mainnet gets slow and expensive at busy times. They run transactions off the main chain in big batches and post the data, or a proof, back to Ethereum. You get low fees and quick confirmations, and the final record still lives on Ethereum.
Most are rollups, of two kinds. Optimistic rollups such as Arbitrum and OP Mainnet assume a batch is valid unless someone proves fraud during a challenge window of about seven days. That window is why a native withdrawal to Ethereum usually takes a week. Base added TEE and ZK proofs in May 2026, and when both agree a withdrawal can finish in about a day. Zero-knowledge rollups such as ZKsync Era, Scroll and Linea post validity proofs that Ethereum checks directly, so withdrawals can finalize once a proof is accepted.
The part that bites is decentralization. Many L2s still run a single sequencer that orders every transaction, and upgrade keys often sit with a small council. Shared frameworks spread that same design to new chains: the OP Stack runs OP Mainnet and other Superchain members, and Arbitrum's stack runs chains such as Robinhood Chain.
A swap that costs $6 on Ethereum mainnet during a busy hour might cost a few cents on an L2 and confirm in about two seconds. It reaches Ethereum later, inside a batch.
Also called: L2, rollup, layer two.
Where does a layer 2 show up in Cashboard?
Cashboard's registry includes seven Ethereum L2s: Base, Robinhood Chain, Arbitrum One, OP Mainnet, Linea, Scroll and ZKsync Era. Every one of them gets Chain status and a watch-only portfolio for a public 0x address. Trending pools cover all seven, Robinhood Chain included. The L2 scoreboard ranks a longer list, every L2 growthepie tracks, by transactions, active addresses, fees and median cost (growthepie data, CC BY 4.0), with the L2BEAT stage and total value secured beside them. Base and Robinhood Chain also get a chain pulse with blocks, gas, TVL and DEX volume.
Frequently asked questions
Is a layer 2 as secure as Ethereum?
Not fully. Rollups post their data to Ethereum, but many still depend on one sequencer and on upgradeable contracts controlled by a small group. Their security is only as good as those parts.
Where can you read more about layer 2?
Related terms
Last reviewed . Market data in Cashboard comes from the providers named on each widget and may be delayed. Nothing here is financial advice.