Validium

Validium is a type of layer-2 scaling solution for blockchains that processes transactions off-chain and posts only validity proofs on the main chain. Unlike other scaling solutions, Validium uses external data availability, meaning the transaction data is not stored on the main chain or by the validators of the layer-2 network itself, but by a separate entity. This approach can significantly increase transaction throughput and reduce costs, as the main chain only needs to verify the proofs, not store the entire transaction data.