Why does it say my JSON is invalid?

Common causes are trailing commas, single quotes, comments or unquoted keys — none are allowed in standard JSON.

Is my data sent to a server?

No. Parsing and formatting happen in your browser.

Can it handle large files?

Files of several megabytes work; very large ones depend on your device's memory.

What indentation is used?

Two spaces per level, the most common style.

Does it change my data?

No, only the spacing changes. Keys and values stay the same.

Can JSON include comments?

Not standard JSON. Remove comments before formatting.

JSON Formatter

Validate and pretty-print JSON with 2-space indentation.

Reading time:: 2 min
Last updated:: 5 August 2026
Price:: Free, no signup

Your text

Results (live)

Type or paste text to see the result.

What the JSON Formatter does

Paste JSON and get it neatly indented and readable, or squeeze it onto one line. If the JSON is broken, you'll see an error telling you what went wrong instead of a confusing blank result.

It's the everyday tool for reading API responses, config files and logs that arrive as one long line.

Why the JSON Formatter is useful

Minified JSON from an API is impossible to read. Indenting it shows the structure — which objects are nested inside which — in seconds.

The validation catches the classic mistakes: a trailing comma, single quotes instead of double quotes, or a missing bracket.

Also known as: json formatter, json beautifier, json validator, free json formatter, online json formatter, json formatter online free, json formatter tool.

How to use the JSON Formatter

1
Paste the JSON
From an API response, a file or browser dev tools.
2
Read the formatted output
Nested objects are indented; errors are reported clearly.
3
Copy or download
Use the tidy version in docs, tickets or code.

Key features

Pretty-print with indentation
Error messages for invalid JSON
Handles deeply nested data
Download as a file

Benefits

Readable API responses
Faster debugging
Data stays on your device

Real-life use cases

API debugging

A developer formats a 3,000-character webhook payload to find the missing customer field.

Config review

A DevOps engineer validates a settings file and finds the trailing comma breaking the deploy.

Tips for the best results

JSON requires double quotes around keys and strings.
Trailing commas after the last item aren't allowed.
Remove tokens and passwords before sharing formatted output.

Conclusion

Paste messy or one-line JSON, read it properly indented, and fix any error it points out.

Frequently asked questions

Why does it say my JSON is invalid?: Common causes are trailing commas, single quotes, comments or unquoted keys — none are allowed in standard JSON.
Is my data sent to a server?: No. Parsing and formatting happen in your browser.
Can it handle large files?: Files of several megabytes work; very large ones depend on your device's memory.
What indentation is used?: Two spaces per level, the most common style.
Does it change my data?: No, only the spacing changes. Keys and values stay the same.
Can JSON include comments?: Not standard JSON. Remove comments before formatting.

Related tools you may need

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JSON Validator — Check whether your JSON parses and see the exact error location.
CSS Beautifier — Reformat compressed CSS with clean two-space indentation.
JavaScript Beautifier — Reformat minified JavaScript with two-space indentation.
SQL Formatter — Beautify SQL queries with keyword capitalization.
XML Formatter — Beautify XML with clean two-space indentation.
Word Wrap Tool — Hard-wrap long lines at 80 characters.
Text Indenter — Add consistent indentation to every line.

Keep exploring

Browse the full tools directory, filter by category, or read guides on the Text Tools Hub blog.