How to format, minify and validate JSON
JSON is the lingua franca of APIs — and it always arrives as a single 8,000-character line when you need to read it most. Formatting with proper indentation turns that wall back into structure: objects, arrays and nesting you can actually scan.
JSON is also stricter than people expect: double quotes only, no comments, no trailing commas. When a payload fails to parse, Invalid JSON tells you nothing — an exact error position tells you everything.
Open the free JSON Formatter — no signup, runs entirely in your browser.
How to use it
- Paste your JSON into the editor.
- Choose Beautify with 2-space, 4-space or tab indentation — or Minify for transport.
- If it fails, the exact error position is shown so you fix the real problem.
- Toggle key sorting for deterministic, diff-friendly output, then copy the result.
Why this one
- Beautify, minify and validate modes in one tool.
- Recursive key sorting for diff-friendly, deterministic output.
- Precise parse errors with position — no hunting through huge payloads.
- Everything runs in your browser; production data stays private.
Frequently asked questions
Why does my JSON fail to parse?
The usual suspects: trailing commas after the last item, single quotes instead of double, unquoted keys, or smart quotes pasted from a document. The error position points at the first offending character.
Can JSON contain comments?
No — standard JSON has no comment syntax. Files with // or block comments are JSONC or JSON5. Strip comments before feeding them to a strict parser.
What does minifying actually save?
All insignificant whitespace: typically 10-30% on pretty-printed documents. The data is identical, just packed — exactly what you want in API payloads and size-limited config files.