A roller is a service that can be run on a ship that accepts L2 Azimuth transactions, bundles them together, and submits the batch to Azimuth on the Ethereum blockchain. Tlon runs the roller used by the default Bridge instance at bridge.urbit.org, but anyone can run their own - especially if they want to submit large volumes of transactions.
Further reading
- Layer 2 for planets: Essential information for planet owners on layer 2 or considering a move to layer 2
- The Gang Solves the Gas Crisis: A casual overview of how naive rollups works.
- Layer 2 Overview: where developers should go to learn about the technical details of naive rollups.
- Custom Roller Tutorial: tutorial on how to set up your own L2 roller.