I will present a trustless application data snapshot architecture based on on-chain hashed lists. I will also demonstrate an implementation of that architecture that is used by HOPR mix nodes to sync data much faster and with very few on-chain reads. The proposed mechanism is an orders of magnitude improvement in indexing speed at the cost of one on-chain hash + read + write of a single storage slot. Our open source base contract can be easily integrated into other smart contracts and combined with various frontend libraries.