Settlement Layer

The settlement layer is the base chain where transactions become final and disputes are resolved — the layer other systems fall back on as the source of truth. In a modular stack, rollups execute transactions quickly and then post proofs or compressed transaction data to a settlement layer such as Ethereum, which verifies them and anchors withdrawals back to the base chain. Settlement is what gives a Layer 2 its security guarantees: if the rollup operator censors users or disappears, the settlement layer still holds the record needed to exit with your funds. Because settlement mainly verifies rather than executes, one settlement layer can secure many chains at once, but it is also the slowest and most expensive part of the stack.