On-chain refers to all activities and data that are recorded directly on a blockchain. This includes transactions, smart contracts, and any other actions that occur within the network. Because these records are stored within the blockchain, they are permanent and immutable, meaning they cannot be altered or deleted once confirmed.Every participant in the network can verify on-chain data, contributing to transparency and security. This openly accessible data structure allows users to trace transaction history and verify asset ownership easily.The opposite of on-chain is off-chain, where activities occur outside the blockchain but may still interact with it. While off-chain transactions can be faster and more scalable, they do not offer the same level of transparency as on-chain recordings. Overall, on-chain activities ensure a higher degree of accountability and trust among users, forming the backbone of many cryptocurrency projects.