Rollup technology is a Layer 2 scaling solution for blockchains, designed to improve transaction speed and reduce costs while maintaining security. It works by processing multiple transactions off-chain, "rolling" them up into a single batch, and then submitting a condensed proof or data summary to the main blockchain (Layer 1). There are two main types: Optimistic Rollups, which assume transactions are valid unless proven otherwise, and Zero-Knowledge Rollups (zk-Rollups), which use cryptographic proofs to ensure validity. Rollups alleviate congestion on networks like Ethereum, enabling higher throughput without compromising decentralization or security. By offloading computation and storage, they lower gas fees and enhance user experience, making blockchain applications more scalable and accessible. This technology is a key step toward mass adoption of decentralized systems.