Mainnet is the term for the real Bitcoin blockchain and network, and is used in contrast with testnet, signet, and regtest networks. Unlike the other networks, which are used for testing purposes, mainnet coins (BTC) have monetary value. When people refer to the Bitcoin network, they are usually referring to mainnet.
Each network has its own blockchain, and its own token. Additionally, addresses have different prefixes for each network. Mainnet addresses begin with ‘1’, ‘3’, or ‘bc1’, while testnet addresses begin with ‘2’, ‘m’, ‘n’, or ‘tb1’. Coins cannot be sent between networks. If mainnet bitcoin is sent to a testnet address, it is destroyed and unrecoverable. The same fate applies to testnet coins sent to mainnet addresses.
