A 0-confirmation transaction is a type of cryptocurrency transaction that has been broadcast to the network but has not yet been confirmed by miners. In other words, it is a transaction that is waiting to be added to a block and added to the blockchain.
During this period of waiting, the transaction is considered unconfirmed and carries a certain level of risk. This is because the transaction could potentially be double-spent, meaning the same funds are used in two different transactions.
Although 0-confirmation transactions are not as secure as confirmed transactions, they are often accepted by merchants and individuals for small transactions due to their speed. However, for larger transactions or when dealing with untrusted parties, it is recommended to wait for the transaction to be confirmed by the network to prevent the risk of double-spending.
Overall, 0-confirmation transactions offer convenience and speed, but come with a level of risk that users should be aware of when using this method of sending and receiving cryptocurrency.