In-depth essays · #20 / 50 · L2 Rollups, Federations & Interoperability

The Interoperability Race: Polygon’s Agglayer vs. ZKsync’s Elastic Network

How zero-knowledge proof aggregation unifies liquidity across sovereign chains

While Optimism unites its western districts under the Superchain banner, ZK ecosystems are building their own cross-chain fabrics: Polygon’s Agglayer and ZKsync’s Elastic Network. Both aim to make dozens of separate chains feel like a single liquid city.

1. The Liquidity Fragmentation Problem in a Multi-Chain World

As launching new L2s became effortless, liquidity splintered across isolated bridges and wrapped tokens, forcing users to manually bridge funds and manage gas balances just to try an app in a neighboring district.

2. Polygon’s Agglayer and the Pessimistic Proof

Polygon’s Agglayer connects heterogeneous chains to a unified L1 bridge contract guarded by the pessimistic proof—a zero-knowledge proof ensuring that no connected chain can ever withdraw more assets from the shared bridge than have been genuinely deposited into it, even if one chain’s internal state is compromised.

In Ethereum City, the DeFi-focused Katana district connects to the broader ecosystem through the Agglayer.

3. ZKsync’s Elastic Network: Native Interop Across ZK Stack Chains

ZKsync Era and Abstract belong to the Elastic Network, where chains built on the ZK Stack share a common proof verification architecture and native account abstraction so users can move across districts with a single passkey wallet.

4. Four Metropolitan Federations Around One Downtown

Instead of hundreds of disconnected islands, Ethereum’s L2 landscape is coalescing into major metropolitan networks—the Superchain, Arbitrum Orbit, the Agglayer, and the Elastic Network—all settling their proofs in downtown Ethereum.

Related districts in the city

Related glossary terms

This essay is an explainer written to help you read the city; it is not investment advice. Facts on this page are as of 2026-10 and may change. If you spot a mistake, please tell us through the contact page.