Features

ZKsync Gateway serves as a settlement aggregation layer for ZK chains, focusing on proof aggregation, interoperability, and cost efficiency. This section describes its key technical features.

Ethereum as the Root Settlement Layer

Chains that migrate to ZKsync Gateway remain fully anchored to Ethereum. Gateway facilitates proof aggregation and coordination, but Ethereum continues to serve as the final verifier and the root of trust for state transitions and asset security.

Assets on Gateway-settling chains are locked on Ethereum, not on Gateway. Any L1-to-L2 communication—such as deposits or token bridging—originates from Ethereum. Gateway does not serve as a standalone execution or custody layer.

Additionally, chains must initially settle on Ethereum before they are eligible to migrate to Gateway. This ensures that their origin and trust model are rooted in Ethereum from the start, and that Ethereum remains the authoritative source for final settlement.

Proof Aggregation

ZKsync Gateway aggregates proofs generated by multiple chains into a single proof. This aggregated proof is then submitted to Ethereum for final verification, reducing the number of proof verification operations required on Layer 1 and lowering associated gas costs. Participating chains benefit from more predictable and reduced settlement costs, while maintaining the security guarantees of Ethereum.

The aggregation mechanism becomes more efficient as the number of chains settling on ZKsync Gateway increases.

Interoperability

ZKsync Gateway provides a shared settlement layer that enables participating chains to communicate with each other. Chains settling on ZKsync Gateway benefit from cheaper and faster settlement, which improves interoperability between chains.

Communication between Gateway-based chains follows standardized mechanisms, while interactions with Ethereum or chains not using Gateway continue to use established bridging protocols. This setup helps reduce the complexity of interchain communication for chains opting into ZKsync Gateway.

Cost Efficiency

Chains settling on ZKsync Gateway reduce their operational costs by taking advantage of proof aggregation and avoiding the high and variable gas costs of direct Ethereum settlement. Settlement fees for submitting proofs to ZKsync Gateway are paid in $ZK tokens, providing a predictable cost structure. Cost savings are influenced by aggregation efficiency and the number of chains using the Gateway.

Finality

When a chain settles on ZKsync Gateway, proof aggregation introduces an additional step before final verification on Ethereum. This can result in slightly longer objective finality times compared to chains settling directly on Ethereum. However, interoperability finality between Gateway-based chains may be faster, as interactions can be completed once the proof is verified on Gateway rather than waiting for full Ethereum settlement.

Chains considering Gateway should weigh the trade-offs between reduced costs, improved interoperability, and L1 finality requirements.