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How to Open a JSON File on Windows, macOS, Mobile, or Online

Double-clicking a .json file gets you nowhere? Here is how to open and read JSON on Windows, macOS, and mobile, plus a browser-based viewer for validating, formatting, and inspecting large files.

What a .json file is, and why double-clicking gets you nowhere

A .json file holds data written in JSON (JavaScript Object Notation): curly braces {} mark objects, square brackets [] mark arrays, and the values are strings, numbers, booleans, or null. Application configs, exported app data, browser extension settings, and most API responses use this format.

The file itself is plain text, which means "opening" it can mean three different tasks: glance at the content, edit a specific field, or find out why the JSON is invalid. Picking the tool for the task saves you from installing an IDE to look at one config file.

When a double-click "fails", it is one of two things: the system has no app associated with .json and asks you to choose one, or a text editor opens a wall of characters with no indentation — sometimes everything on a single line. Neither means the file is broken.

The quickest option: open the .json file in a browser

When you just need to see what is inside, the online JSON viewer requires no installation:

  1. Drag the file onto the page, or paste its content into the left pane.
  2. A collapsible tree appears on the right; expand objects and arrays level by level.
  3. If the content is invalid, you get the exact line, column, and reason instead of a bare "invalid" message.
  4. Format the content with indentation to keep a readable copy, then copy or download it.

Everything is parsed locally in your browser and nothing is uploaded. For an API response you just captured or a config snapshot a colleague sent over, this open-inspect-close path usually takes under a minute.

How to open .json files on Windows

Read the source with Notepad

Right-click the file, choose Open with, and pick Notepad. Zero setup, fine for checking what a file contains. The limits are just as clear: no syntax highlighting, no folding, and minified JSON is unreadable. If non-English text looks corrupted, reopen the file with UTF-8 encoding.

Edit regularly with VS Code or another code editor

Visual Studio Code, Notepad++, and their peers support JSON natively: syntax highlighting, block folding, bracket matching, and go-to-line. VS Code also flags JSON syntax errors as you type. If .json files are something you edit as part of your work, install an editor once and be done.

Quick looks: drag into the browser

For structure and error locations, drag the file into the online viewer above — nothing to install.

How to open .json files on macOS

The built-in TextEdit has a well-known trap: it defaults to rich text (RTF). Opening a .json file can prompt you about plain versus rich text, and saving from the wrong mode wraps the file in RTF markup. Check Format → Make Plain Text first, or skip straight to VS Code.

Day to day, macOS works the same as Windows: an editor for changes, a browser tool for reading. There is no platform-specific advantage either way.

How to open .json files on mobile

Neither iOS nor Android ships with anything that handles .json. Tapping the file usually ends in "unsupported format". Two practical paths:

  • Move the file to a computer and handle it there — simplest in almost every case.
  • Open a browser-based JSON viewer on the phone and paste the content in, or hand the file over via the share sheet. Reading on mobile is fine; editing long files is not.

After it opens: three recurring problems

One long line with no spaces. That is minified JSON — small to transfer, unreadable for humans. Any parser expands it into an indented version; a plain text editor cannot help here.

The tool says the JSON is invalid. Common causes: a trailing comma, an unquoted key, single quotes, or comments (the JSON standard has none). A viewer that reports the exact line and column beats scanning by eye.

Should anyone else see this file? .json files routinely contain API keys, internal hostnames, or user data. Before pasting content anywhere, confirm the tool processes it locally and consider how sensitive the file was in the first place.

Frequently Asked Questions

Can Notepad open a .json file?

Yes. A .json file is UTF-8 plain text, so Notepad can read and edit the source. It will not highlight syntax or fold nested structures, and a minified one-line file is nearly unreadable there.

Nothing happens when I double-click a .json file. What now?

Neither Windows nor macOS associates .json with an application by default, so the system asks you to pick a program. Any text editor shows the source; for a readable tree view, drag the file into a browser-based JSON viewer.

Why does my .json file open as garbled text?

Usually the editor guessed the wrong encoding. JSON is specified as UTF-8; reload the file with UTF-8 encoding and the text recovers. If it stays garbled, the file itself was written in another encoding and needs fixing at the source.

Is it safe to paste a .json file into an online tool?

It depends on the service. The viewer on this site parses everything locally in your browser and never uploads the content. Check a service's privacy statement before pasting JSON that contains API keys or internal data.

My .json file is too large for editors to open. What can I do?

Hundred-megabyte files overwhelm editors that render every character. Inspect the structure from a command line first (for example, read the key names in Python), or ask the exporter to split or compress the file. Browser-based viewers handle large files better than editors, but they also have limits.