Rollups in simple terms: how L2s sell you Ethereum at a discount

Ethereum is expensive because every transaction is verified by the entire network. A rollup solves this boldly and elegantly: it executes thousands of transactions on its own, and records only a compressed summary on Ethereum. The security of Ethereum, at a fraction of the cost.

Optimistic vs ZK

Optimistic rollups (Arbitrum, Optimism, Base) publish the result "on trust": it is considered valid if no one has proven fraud within a window of several days. Hence the week-long wait when withdrawing via the native bridge. ZK-rollups (zkSync, Starknet, Linea, Scroll) attach a mathematical proof of correctness to each batch - more expensive to produce, but finality is almost instant.

The main catch: the token is not the network

The success of a network does not guarantee growth of its token. For most L2 tokens, the only function is DAO voting: network fees are not paid out to them, and value does not accumulate. The sector has shown the same pattern for years: activity grows, while tokens fall under pressure from fund unlocks. Before buying an L2 token, the first question is not "is the network good" but "why does this network need a token and who gets the fees".

L2 coin metrics are in the catalog, breakdowns are in the L2 section.