How to Open a JSON File
A .json file is plain text, so nothing special is needed to open one. The real question is what you want to do with it: glance at the contents, explore the structure, change a few values, or get the data into a spreadsheet. Those are four different jobs and they have four different answers, all of them free.
Fastest: drag it into a browser
Every modern browser opens JSON files. Drag the file into a Chrome, Firefox or Edge window, or press Ctrl/Cmd+O and pick it. Firefox renders an interactive collapsible view by default; Chrome shows raw text.
For a one-off “what’s in this file?” check, that beats installing anything.
Most readable: an online viewer
Raw JSON is hard to read as text, and minified JSON on a single line is close to impossible. Paste the contents into the JSON Viewer to explore a collapsible tree with color-coded types, or into the JSON Formatter for cleanly indented text you can copy back out. Both run in the page itself, so you can inspect a file without sending it to a processing server.
For editing: a code editor
To change the file, use a text editor, ideally a code editor. VS Code (free, and on Windows, Mac and Linux) is the standard choice: it colors the syntax, flags errors as you type and formats on save.
The built-in editors work too. Notepad on Windows and TextEdit on Mac open JSON fine, with one catch on the Mac side: TextEdit’s rich-text mode will mangle a file, so switch it with Format → Make Plain Text first. Never edit JSON in Word or Google Docs. Both silently replace straight quotes with typographic ones and break the file.
Into a spreadsheet: convert to CSV
Excel and Google Sheets don’t open JSON directly in any useful way. Excel’s Power Query can, but it is buried several menus deep. The simple path: if the file holds an array of records, run it through the JSON to CSV converter, download the CSV and open that. One row per record, one column per field, ready for sorting and pivot tables.
On a phone or tablet
The browser route works everywhere. Open this site’s viewer or formatter on the device, then open the JSON file in any app that shows text, whether that is Files or a mail attachment preview, and copy the contents across. No app install needed.
Editing without breaking the file
JSON’s syntax is unforgiving, and one stray comma is enough for a program to refuse the whole file. Three habits prevent most of the damage. Keep your quotes straight ("); curly ones are the giveaway that a document editor got hold of the file. When you delete the last item in a list, delete the comma before it too. And after any edit, paste the file into the JSON Validator before you save over the original. It pinpoints the exact line of any mistake, and the common JSON errors guide has the fix for each message you might see.
What’s actually in a JSON file?
Structured data: settings for an app, a data export, an API response somebody saved. It reads as nested labels and values, with text in quotes, bare numbers, lists in square brackets and groups in curly braces. If the format itself is new to you, What Is JSON? explains the whole thing in five minutes with examples.