JSON Formatter
Format, beautify and validate JSON data with syntax highlighting.
Got a wall of minified JSON that is hard to read? Paste it here and format it with clean indentation and syntax highlighting. You can also minify JSON or run a quick validation check when something refuses to parse.
What This Tool Does
- Beautify - Takes compressed JSON and adds indentation and line breaks so you can read it.
- Minify - Removes extra whitespace to shrink the output.
- Validate - Checks whether the text is strict JSON and returns the parser error if it fails.
- Highlight - Colors keys, strings, numbers, booleans and null values in the formatted output.
Why JSON Breaks
Most JSON errors come from a few repeat mistakes. Trailing commas are common because JavaScript allows them in objects and arrays, but JSON does not. Single quotes are another one. JSON requires double quotes for keys and string values.
Other common problems include unquoted property names, comments, missing brackets and unescaped line breaks inside strings. If a config file works in one app but fails in another, it may be JSONC or JSON5 rather than strict JSON.
JSON vs. JavaScript Objects
They look similar, but they are not the same format. JavaScript objects can be more relaxed. JSON is stricter because it is meant for data exchange between different systems. If you copy a JavaScript object into a JSON API request, remove comments, trailing commas and single quotes first.
Working with Large JSON
The formatter is useful for API responses, webhook payloads and config snippets. For very large files, use a desktop editor or a command-line tool like jq. Browser tools are best for quick inspection, not for multi-megabyte production logs.
How to Use
- Paste raw or minified JSON into the input box.
- Click Format to beautify it.
- Click Validate if you only want to check the syntax.
- Copy the formatted or minified output.
Frequently Asked Questions
How do I use the JSON Formatter?
Paste JSON and format it. If there is an error, fix the first reported issue and run it again. JSON parsers often stop at the first serious problem.
Why is my JSON invalid?
The most common causes are trailing commas, single quotes, missing quotes around keys and bad escaping. Check the line near the first error. One small syntax issue can break the whole file.
Why does JSON work in JavaScript but fail here?
JavaScript object literals are more forgiving. JSON is stricter and does not allow comments, trailing commas or unquoted keys. If an API asks for JSON, use strict JSON rules.
Can I minify JSON?
Yes. Minifying removes extra spaces and line breaks, which is useful for compact API payloads. Keep a formatted copy for editing because minified JSON is harder to read.
Is it safe to paste API data?
Treat private API data carefully. Avoid pasting secrets, tokens, passwords or customer records into public tools. For sensitive work, use a trusted local formatter.