JSON Formatter

JSON Formatter

The JSON Formatter pretty-prints, validates and minifies JSON entirely in your browser. Well-formatted JSON is far easier to read and diff, while minified JSON is smaller on the wire — this tool does both, and pinpoints syntax errors by line and column.

Why use JSON Formatter

  • Pretty-print with 2-space indentation or minify to a single line.
  • Validate with the exact line and column of the first error.
  • Syntax highlighting and line numbers for fast scanning.
  • Upload, drag-and-drop or download JSON; handles large files.

How to use JSON Formatter

  1. 1Paste or drop JSON. Paste JSON into the editor, or drag a .json file onto it.
  2. 2Format or minify. Click Format to pretty-print or Minify to compact it; invalid JSON is flagged with the error location.
  3. 3Copy or download. Copy the result or download it as a .json file.

Frequently asked questions

Where does my JSON go?
Nowhere — it is parsed and formatted entirely in your browser. No data is sent to any server.
Why is my JSON invalid?
Common causes are trailing commas, single quotes, or unquoted keys. The validator points to the exact line and column of the first error.
Can it handle large JSON files?
Yes. Formatting and validation are efficient; syntax highlighting is skipped above ~200 KB to keep it instant.

Developer notes

Most “invalid JSON” errors come from trailing commas, single quotes, comments or unquoted keys — none of which are valid JSON. JSON is always UTF-8 and keys must be double-quoted strings.

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