Decentralized sequencer protocol Espresso Systems has launched its fourth testnet, the Gibraltar testnet, and has made it open to Arbitrum developers.

Layer 2 collators are responsible for processing and sorting transactions from the memory pool and placing them into blocks. Their function can be compared to that of validators on a monolithic blockchain or layer 1 network, and they play an important role in securing the network.

The problem with today’s collators is that many rollups run their own collators and execution environments, and zero-knowledge solutions run their own provers. This introduces trust assumptions and centralization issues.

In addition to enabling Arbitrum developers to test their dapps using the shared sorter network, the Gibraltar testnet will also see external node operators running the network for the first time.

Espresso provides a shared sorter network, a distributed consensus system shared between rollups — so far it has integrated with Optimism, Cartesi, and Polygon zkEVM via testnets.