How to format JSON
- Paste your JSON into the box above.
- Pick an indent of 2 spaces, 4 spaces or tabs.
- Read the formatted result in the output box.
- Fix any error at the line and column the tool reports.
- Copy the result or download it.
What this JSON formatter gives you
- Indents of 2 spaces, 4 spaces or tabs to match your project.
- The exact line and column of any syntax error.
- Plain language notes on common mistakes.
- A count of keys and objects plus the deepest level.
- Key order kept exactly as in your source.
- Live results as you type with no upload.
Why use a JSON formatter?
An API response often arrives as one huge line. Somewhere inside it a field is missing. Or a value is text where you expected a number. Or an array sits empty when it should hold data. That single line is almost impossible to read. So a JSON formatter is usually the first step with any new JSON.
Indents turn structure into something your eye can follow. Each level of nesting shows up as depth. Keys at the same level line up. An array of objects reads like a list and not a wall. The data does not change at all. Only the layout changes.
The mistakes that break JSON
| Mistake | Example | Fix |
|---|---|---|
| Trailing comma | [1, 2, 3,] | Remove the last comma |
| Single quotes | {'a': 1} | Use double quotes |
| Unquoted keys | {name: "x"} | Quote every key |
| Comments | // note | Delete them |
| Undefined or NaN | {"a": NaN} | Use null or drop the key |
The trailing comma is the most common error by far. JavaScript allows it. JSON does not. Each of these mistakes gives a short engine message with a character position nobody can find. This tool turns that position into a line and column. Then it says what went wrong.
How to read the structure summary
Next to the formatted output you get a count of keys, objects and arrays. You also see the deepest nesting level.
Depth is the number to watch. A file past five or six levels gets hard to use in code. It often means the structure would work better if someone flattened it.
The key count is a quick sanity check. Say an API promises twelve fields and the count shows nine. Three are missing before you write a single line of code to find them.
Does a JSON formatter change your data?
No. JSON ignores whitespace between items. So a formatted document and its minified version give exactly the same value. The tool keeps your key order too.
One small thing changes. Numbers get a standard form. So 1.50 becomes 1.5 because both are the same number. Need the exact written form? Store the value as a string.
Which indent should you choose?
- 2 spaces: the web default. Deep documents stay on screen.
- 4 spaces: easier to scan for wide but shallow documents.
- Tabs: each reader picks their own width in an editor.
Common JSON formatter questions from developers
The error points at the last line
A bracket or brace never closed. The parser only noticed at the end. Look earlier for the opening that has no match.
My JSON came from a log with extra text
Remove any timestamp or label before the first brace. Then paste again.
Tips for a smooth JSON formatter session
- Paste the whole response and not a piece of it.
- Fix the first error the tool reports before you look at others.
- Keep a copy of the raw text in case you need to compare later.
- Use the same indent your team uses so diffs stay clean.
- Check the key count against the API docs.
A formatted file also helps in code review. A teammate can read the change line by line. A one line blob gives them nothing to point at.
Who uses a JSON formatter?
Developers read API responses. QA testers compare expected and actual results. Data analysts inspect exports. Students learn how JSON nests. Support teams read webhook payloads from customers.
Your JSON stays private
The tool parses and formats everything in your browser. API responses with tokens or customer data never leave your device. Need only a yes or no check? Use the JSON validator. Want the smallest file? Try the JSON minifier. Want to compare two files? The JSON beautifier can sort keys first.