The Espresso Rollup Node Proxy is a Go service that sits between clients and an OP stack L2 full node to enforce Espresso finality. Instead of relying solely on Ethereum for finality, clients can use an Espresso-specific block tag (default: "espresso") in their JSON-RPC calls; the proxy resolves that tag to the latest L2 block number confirmed by Espresso's HotShot consensus.

Proxy — Intercepts every JSON-RPC request (including batch requests) before forwarding it to the full node. Any occurrence of the Espresso tag in the request params is replaced with the current Espresso-finalized L2 block number, then the request is forwarded transparently.

Verifier — A background loop continuously compares the next batch produced by the Espresso streamer against the corresponding block on the OP full node. On a match, the loop advances the streamer and persists the new L2 block number to disk; on a mismatch, it retries at the next interval.

Store — Persists the Espresso-finalized L2 block number and HotShot fallback position to a JSON file so state survives restarts.

The proxy starts in non-Espresso mode and automatically switches to Espresso mode once the verifier confirms the first batch.

Enter the Nix dev shell and use just.

nix develop

Run just test to execute the tests, or run just with no arguments to list all available recipes.

Copyright (c) 2022 Espresso Systems. The Espresso Rollup Node Proxy was developed by Espresso Systems. While we plan to adopt an open source license, we have not yet selected one. As such, all rights are reserved for the time being. Please reach out to us if you have thoughts on licensing.

DISCLAIMER: This software is provided "as is" and its security has not been externally audited. Use at your own risk.

DISCLAIMER: The Go packages provided in this repository are intended primarily for use by the binary targets in this repository. We make no guarantees of public API stability. If you are building on these packages, reach out by opening an issue to discuss the APIs you need.