What is a .json file?
A .json file is a plain text file containing data written in JSON — JavaScript Object Notation. Despite the name, it isn't tied to JavaScript specifically; it's a universal, language-independent way to structure data as key-value pairs, lists, and nested objects. Apps use .json files to store settings, save data, and exchange information with other systems, which is why you might encounter one after exporting data, downloading an API response, or installing certain apps and browser extensions.
Opened in a plain text editor, a .json file just looks like text — curly braces, square brackets, quoted words, and colons. There's nothing to "run" or install; it's inert data, not a program, so opening one to look at it is always safe.
Opening a .json file on Windows
Right-click the file, choose "Open with," and select Notepad (or any text editor). You'll see the raw contents immediately. If the file is large or minified — packed onto one line with no spacing — Notepad will show it as a single unreadable wall of text; skip ahead to the formatting step below to fix that.
Opening a .json file on Mac
Right-click the file, choose "Open With," and select TextEdit. As on Windows, this shows the raw text as-is, with the same minification caveat for files packed onto one line.
Opening a .json file in your browser (no install needed)
The fastest, most readable way to open a .json file — especially a large or deeply nested one — is to drop it straight into a browser-based JSON viewer. Instead of a wall of raw text, you get a collapsible, color-coded tree you can expand, search, and navigate, with no software to install. Our JSON Viewer does exactly this: drag your file in and it renders instantly, entirely in your browser, without uploading the file anywhere.
My .json file looks like one giant unreadable line — now what?
That's minification: many tools save .json files without extra spaces or line breaks to keep file size small, which is efficient for machines but unreadable for people. Paste the contents into our JSON Formatter and it will instantly re-indent it into a readable structure — this is often the single fastest fix when a .json file "looks broken" but is actually just densely packed.
Editing a .json file
If you need to change values rather than just view them, a plain text editor works for small edits, but it's easy to break the syntax (an extra comma, a missing quote) without realizing it. A dedicated JSON Editor with syntax highlighting and real-time validation catches those mistakes as you type, instead of only failing later when something tries to parse the file.