Runtime, also known as execution time, is the final stage of a computer program’s lifecycle, during which the code is executed by the computer’s central processing unit (CPU). Runtime can also refer to the amount of time that a program is active, beginning when it is executed (or opened) and ending when it is closed. In general, when a program is in the runtime phase, it makes use of Random Access Memory (RAM). Blockchains and computer networks are frequently designed with a pre-built runtime environment that, when required, implements portions of an execution model.