Validium is a blockchain scaling solution that processes transactions and stores data off-chain to improve the main Transaction processing performance and efficiency of network blockchain.

What is capacity expansion? How is it achieved? Please refer to the entry "What is Layer 2 Network".

In other words, it moves the execution layer and data availability layer of the underlying blockchain off-chain. Validium uses validity proof to ensure the integrity of off-chain transactions, which is the same as zero-knowledge roll-up. However, zero-knowledge roll-up publishes compressed transaction data on mainnet, while Validium stores transaction data off-chain to further reduce costs and improve performance.

What is a zero-knowledge proof? How does it work? Please refer to the entry "What is a zero-knowledge proof".

Validium relies solely on the mainnet for settlement and consensus. Immutable X is a Validium. Arbitrum Nova also moves execution and data availability off-chain. But it does not use validation proofs, so it is not strictly speaking a Validium.

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