Recursive rollups are a type of rollup whereby multiple rollup layers exist inside or on each other. In such constructions, the 'lower' layer can natively verify the validity of a 'higher' layer and nest a validity proof within a subsequent validity proof. Recursive rollups can accommodate multiple layers through a recursive proof system. A recursive proof system generates proofs in parallel for different blocks and aggregates them into one single block proof submitted to the L1 (layer one) blockchain, meaning one proof can verify other proofs. Recursive rollup architecture offers applications the benefit of scalability and customizability, as it is feasible to develop application-specific rollups, secured by lower levels rollups, with varying design considerations for data availability.