2026-05-10 –, Sladkovský Stage
POD is a recursive, logical, client-side proof system we've been building at 0xPARC. Recursive client-side proving is newly feasible and it changes what ZK is for: not just hiding data from verifiers, but letting parties prove to each other and compose claims across protocols. I'll cover the system, the language, and real-world experiences of building with it.
POD is a proof system we've been developing at 0xPARC for a couple of years now. Three architectural principles:
- Recursive. Proofs can take other proofs as inputs.
- Logical. Claims are statements in a logic language (Podlang), not hand-rolled circuits per application.
- Client-side. Proving happens on the user's device, not on a prover service.
This makes ZK proofs easy to write, feasible to run client-side, scalable via recursion, and designed for interoperability through the use of a composable logic language.
This system also builds on our experience of proof-carrying data in systems like Zupass. It moves us from a world where client-side proving is solely a privacy technology, to a world where whole systems can be designed around proof-carrying data. PODs are created and consumed on both the client and server sides, or on all participant devices in a peer-to-peer network.
The technology is open source and published as open research. It is both a usable system but also a design for an interoperable ZK architecture which we hope will influence others.
Rob Knight is a Research Engineer at 0xPARC. He was a maintainer of the Zupass project, and more recently a contributor to the POD project.