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JSON Formatter & Validator

Paste JSON to pretty-print it, find errors or minify it.

Runs in your browser · files never leave your device

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What you get with the JSON Formatter & Validator

  • Format, minify and validate with the exact line and column of any error
  • Repair common mistakes: single quotes, comments, unquoted keys and trailing commas
  • Collapsible tree view and a JSONPath-style query box
  • Convert to YAML, XML, TypeScript interfaces, CSV or an escaped string
  • Sort keys A-Z, choose 2 or 4 spaces or tabs
  • Open files, download results and see size, key count and depth

How to use the JSON Formatter & Validator

  1. 1

    Paste or upload JSON.

  2. 2

    Click Format, Minify or Validate.

  3. 3

    Copy or download the result.

Frequently asked questions

Are my files uploaded to a server?+

No. This tool runs entirely in your browser - your files never leave your device, so it is private and works even on a slow connection.

What is JSON and why does it break?

JSON (JavaScript Object Notation) is the standard text format for exchanging data between apps and APIs. It is strict: keys and strings need double quotes, no trailing commas, no comments. Data copied from JavaScript code, Python output or hand-written config often breaks those rules, which is when a validator that points to the exact line becomes useful.

Handy things you can do here

  • Find the error: the message shows line and column.
  • Repair: convert single quotes, remove comments and trailing commas, quote bare keys, and turn Python None, True and False into JSON.
  • Explore: open the tree and collapse the parts you do not need.
  • Extract: use paths like $.team[*].name to pull values out of large responses.
  • Convert: generate TypeScript interfaces from an API response, or a YAML config from JSON.

New to APIs? Read what an API is and how JSON fits in.

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