Timelock

A timelock is a feature in Bitcoin that restricts when a transaction’s outputs can be spent. It lets you set a condition so the recipient can only access the funds after a certain point in the future, either defined by a particular block height or a specific Unix timestamp. Every Bitcoin transaction includes a field to set a timelock, but it’s usually left empty unless this delay is required. Timelocks are essential for advanced functions like Hashed Timelock Contracts (HTLCs), which enable systems such as the Lightning Network for faster, off-chain payments.