What is Testnet?

A testnet is a sandbox or testing environment for a blockchain network typically made available for development purposes prior to a mainnet launch. Testnets are commonly used to ensure that the blockchain system is adequately secure and functional in accordance with its intended design. Once the testnet has been audited and pressure-tested, developers often fix bugs or add new features to the project's mainnet prior to launch. Testnets are generally not meant to be directly converted into mainnets, so they are usually unable to broadcast or verify network transactions in the same way that a mainnet system is able.