INI File — What It Is and What Opens It

What INI is

INI is a plain-text format you can open in any editor. It is used for editing.

The extension is .ini, and the full name is INI Configuration. Both matter less than what the file can hold, which is what the rest of this page is about.

Where INI came from

It dates from 1985.

A format that has been readable for that long is a format worth trusting with something you want back in ten years.

The specification is public

Anyone can implement it without asking permission or paying a licence, which is why it turns up in so many programs and why files written twenty years ago still open.

It is a legacy format

It still opens everywhere and is still written by older tools, but nothing new is being built around it. Convert what you mean to keep, and do not choose it for something starting today.

You can leave notes in it

INI has a comment syntax, which is the difference between a file a person maintains and one a program writes. Comments are the first thing lost converting to a format without them, and nothing warns you.

What opens INI

Notepad and Visual Studio Code read it, and so do most programs of the same kind.

If a file will not open, the format is rarely the problem — it is more often that the program predates it. Converting to something older is the reliable way past that, and it is what the rest of this site is for.

Opening it in a browser

No browser reads it.

That is the single most common reason to convert it: not that the format is bad, but that the place you want to show the file cannot read it.

It is a working format

INI is meant to be opened and changed. Keep the file in this format for as long as the work is going on, and export from it whenever a finished copy is needed.

The facts, in one place

Identifiers and provenance for the INI format.
Extension	.ini, .cfg, .conf
Media type	text/plain
First published	1985

What is an INI file?