What Does JSON Stand For? What a JSON File Is and How to Open One
Quick answer
JSON stands for JavaScript Object Notation. It is a plain text format for storing and sending data as names and values. A JSON file ends in .json and opens in any text editor, such as Notepad on Windows or TextEdit on a Mac. Web browsers can open it too.
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If you were wondering what does JSON stand for, the short version is above. Below you will find what the data inside a JSON file looks like, how to open one on any device, and how to fix the errors that stop a file from opening. If the file you have is one long line, paste it into our JSON formatter to make it readable.
What does JSON stand for, and what is a JSON file?
A JSON file is a text file that holds data in a fixed structure of names and values. Apps use JSON to save settings, and websites use it to send data between a server and your browser. Most people say it like the name “Jason”.
JSON grew out of JavaScript, but almost every programming language can read and write it. Douglas Crockford wrote the first formal description, RFC 4627, in 2006. Today JSON is defined by RFC 8259 (December 2017) and by the ECMA-404 standard, which describe the same rules.
Here is a small example:
{
"name": "Tool Holdall",
"launched": 2026,
"free": true,
"tools": ["Word Counter", "JSON Formatter"],
"owner": null
}The six types of value in JSON
Every value in a JSON file is one of six types: four simple ones and two that hold other values.
| Type | Example | Notes |
|---|---|---|
| String | “Tool Holdall” | Text inside double quotes |
| Number | 2026 or 4.5 | No quotes, no leading zeros |
| Boolean | true or false | Always lowercase |
| Null | null | Means no value |
| Object | { “name”: “value” } | Names and values inside curly brackets |
| Array | [ “a”, “b” ] | A list inside square brackets |
Key facts about the JSON format
- File extension: .json
- Media type: application/json
- Text encoding: RFC 8259 requires UTF-8 when JSON is sent between separate systems.
- Names: must be in double quotes. Single quotes are not valid.
- Comments: not allowed in standard JSON.
- Numbers: NaN and Infinity are not allowed.
How to open a JSON file
Any program that opens plain text can open a JSON file. Pick the method that suits your device.
On Windows
- Right click the file and choose Open with.
- Pick Notepad to see the raw text.
- For an easier view, drag the file into a Chrome, Edge or Firefox tab. Firefox has a JSON viewer built in that folds the data into sections.
On a Mac
- Control click the file and choose Open With, then TextEdit.
- If you edit it, choose Format then Make Plain Text before you save, so TextEdit does not add formatting.
- You can also drag the file into Safari, Chrome or Firefox to read it.
On an iPhone or Android phone
Phones often have no app set for .json files. Save the file to your Files app, open it with a text editor app, or copy the text and paste it into an online formatter in your browser.
In Excel
Excel for Windows can import JSON as a table. Go to Data, then Get Data, then From File, then From JSON. This works best when the JSON is a list of records with the same fields.
Online
Paste the text into our JSON formatter. It indents the data, checks it against the JSON rules and runs in your browser, so the data is not sent to a server.
Why a JSON file will not open or shows an error
Most errors come from small syntax slips. JavaScript allows some of these, but strict JSON does not.
| Problem | Wrong | Right |
|---|---|---|
| Comma after the last item | { “a”: 1, } | { “a”: 1 } |
| Single quotes | { ‘a’: ‘x’ } | { “a”: “x” } |
| Names without quotes | { a: 1 } | { “a”: 1 } |
| Comments | { “a”: 1 // note } | Remove the comment |
| Values JSON does not know | { “a”: undefined } | { “a”: null } |
| Capital letters in true, false or null | { “a”: True } | { “a”: true } |
A hidden byte order mark at the start of the file can also cause trouble. RFC 8259 says JSON sent over a network must not start with one, so save the file as UTF-8 without BOM if a program rejects it.
JSON, XML and CSV: which is which?
| Format | Best for | What it looks like |
|---|---|---|
| JSON | Web data, app settings, nested data | Names and values in curly and square brackets |
| XML | Documents and older systems | Opening and closing tags, like HTML |
| CSV | Flat tables for spreadsheets | One row per line, values split by commas |
JSON on websites: JSON-LD
JSON-LD is JSON used to describe a page to search engines, such as the author of an article or the price of a product. It sits in a script tag in the page code. See our schema markup examples for ready to copy JSON-LD, or build your own with the schema markup generator.
Frequently asked questions
What does JSON stand for?
JSON stands for JavaScript Object Notation. It is a text format for storing and sending structured data.
Is a JSON file just a text file?
Yes. A JSON file is plain text that follows the JSON rules, so any text editor can open it.
Can JSON have comments?
No. Standard JSON has no comment syntax. Some tools, such as VS Code settings files, use a variant called JSON with Comments, but strict JSON parsers reject comments.
Do I need to know JavaScript to use JSON?
No. JSON came from JavaScript, but almost every programming language can read and write it, and you can read it in any text editor.
What is the difference between HTML and JSON?
HTML describes how a web page is laid out and shown. JSON only holds data. A page often loads data as JSON and then shows it using HTML.
