The mainnet, or main network, is the official and functional version of a blockchain, on which transactions are real and cryptocurrencies have true value. It is on the mainnet that users actually interact with the protocol, sending funds, executing smart contracts, or using decentralized applications (dApps).

Before the launch of a mainnet, projects generally go through a testnet (test network) phase, used to detect bugs and test features without financial risks.

The launch of a mainnet is often a key milestone in the life of a crypto project, as it marks the transition from a prototype to an operational product, demonstrating the protocol's ability to function autonomously and securely.