OneTool

JSON Formatter & Validator

Format, minify, and validate JSON without sending data to a server.

Output mode

Valid JSON

What is this tool?

JSON (JavaScript Object Notation) is a lightweight data format used in APIs, config files, and web apps. This formatter validates your JSON and lets you switch between human-readable pretty-print and compact minified output.

How to use it

  1. Paste or type JSON into the input box.
  2. Choose Pretty print or Minify.
  3. Fix any validation errors shown with line/column details, then copy the output.