Prover

In any proof system there are two roles: the prover, who does the heavy work of producing a proof, and the verifier, who checks it cheaply. For a ZK rollup, the prover re-executes a batch of transactions and turns the execution trace into a SNARK or STARK, using large amounts of computing power, typically GPUs and sometimes dedicated hardware.

Proving cost and speed decide how cheap and fast a ZK rollup can be. General-purpose zkVMs have made it possible to prove ordinary programs, and in 2025 several teams demonstrated proving Ethereum blocks in close to real time. Decentralised prover networks and marketplaces now let rollups and apps buy proofs from competing operators instead of running their own machines.

A centralised prover is a liveness risk: if it stops, withdrawals and finality wait, although it cannot forge invalid state. Proving hardware is concentrated among a few specialists, and costs vary widely between proof systems. Prover is also used in other contexts, such as proofs of storage, so the meaning depends on the network discussed.