Interpreter

An interpreter is a program that executes source code directly, translating and running it statement by statement instead of producing a separate machine-code file first. Python, JavaScript and PHP are commonly run by interpreters.

Interpreted programs are quick to start and easy to test, because changes can be run immediately, and errors appear when the faulty line is reached. They are usually slower than compiled programs, although modern interpreters often use just-in-time (JIT) compilation to speed up frequently run code.