I have two questions about Epoxy:

  • How does a zk-rollup on Tezos differ to the Smart Contract Optimistic Rollups? Will this make SCORU obsolete?
  • I read that it is possible to test Epoxy zk-rollups on Mondaynet in the announcement. But I do not see how - I cannot find any documentation?

1 Answer 1


A ZK rollup is a rollup that uses Zero-Knowledge proofs to guarantee the validity of the commitments published on layer-1. These proofs can be immediately checked by the Tezos protocol leading to instant finality of the rollup states.

This means for example that withdrawing an asset from the rollup to layer-1 can be done immediately after the publication of the state that includes this order. By contrast, smart rollups require waiting for two weeks (when the refutation period is passed).

Zero Knowledge proofs are a lot more expensive than optimistic commitments. While smart rollups allow general computations with no significant limitations in terms of computational power or bandwidth, the cost of producing a ZK proof is so high that even a standard cryptographic signature check is considered too costly to be implemented in a ZK rollup in production. In terms of expressivity, ZK proofs are therefore very far from what smart rollups offer.

Epoxy is a demonstration that Tezos coredevs take ZK proofs seriously: we have a competitive ZK prover as well as a realistic integration of a transactional rollup in the protocol. This integration has reached MondayNet and can indeed be tested. However, the tooling is minimal and is indeed not documented because that's probably not how Tezos end-users will take advantage of ZK proofs in the future.

To conclude, smart rollups are far from obsolete. You can start building on top of them. ZK proofs are still under active development and we will do our best to smoothly integrate them in your DApps too.

  • Thank you for the detailed anwer! Looking forward for more information about zk-rollups
    – user9011
    Feb 20, 2023 at 13:34

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