Features

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

Ethereum as the Root Layer

ZKsync 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-connected chains are locked on Ethereum, not on ZKsync 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 launch with Ethereum as their origin before they are eligible to migrate to Gateway. This ensures that their trust assumptions remain grounded in Ethereum from the start, and that Ethereum remains the authoritative source for final verification.

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 verification costs, while maintaining the security guarantees of Ethereum.

The aggregation mechanism becomes more efficient as the number of chains integrating with ZKsync Gateway increases.

Interoperability

ZKsync Gateway provides a shared proof layer that enables participating chains to communicate with each other. Chains integrated with ZKsync Gateway benefit from cheaper and faster cross-chain interactions, which improves interoperability between chains.

Communication between Gateway-connected 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 using ZKsync Gateway reduce their operational costs by taking advantage of proof aggregation and avoiding the high and variable gas costs of submitting proofs directly to Ethereum. Proof submission fees via 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 utilizes ZKsync Gateway for proof submission, an additional aggregation step is introduced before final verification on Ethereum. This can result in slightly longer objective finality times compared to chains verifying proofs directly on Ethereum. However, interoperability finality between Gateway-connected chains may be faster, as interactions can be completed once the proof is verified by Gateway rather than waiting for Ethereum-level finality.

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