TypeScript is a programming language developed by Microsoft that builds on JavaScript by adding static typing.

In simple terms:

• It lets you declare types for variables, function parameters, and objects (e.g., string, number, boolean, custom interfaces).
• This helps catch errors before you run your code, during development or compilation.
• TypeScript code is then compiled (transpiled) into plain JavaScript, which can run anywhere JavaScript runs (browsers, Node.js, Deno, etc.).

In short — TypeScript is JavaScript with types, designed to make large-scale, reliable, and maintainable codebases easier to write and debug.