Data & Formats

JSON Formatter & Validator

Beautify messy JSON, minify it for production, or find exactly where it's broken — with plain-English errors that point to the line and column.

Indentation

Output

Formatted or minified JSON will appear here

  • Format & minify

    Pretty-print with 2 spaces, 4 spaces or tabs, or strip all whitespace to make API payloads smaller.

  • Errors you can fix

    Trailing commas, single quotes, missing commas and unclosed brackets are explained with the exact line and column.

  • Nothing gets rounded

    Numbers and strings are copied exactly as written, so big IDs and precise decimals stay untouched.

Free online JSON formatter and validator

JSON (JavaScript Object Notation) is the format almost every API, config file and no-code automation tool speaks. When a response arrives as one long line, or a webhook fails with “invalid JSON”, paste it here to make it readable or find the problem in seconds.

How to use it

  1. Paste your JSON into the input box, or tap Sample to try it out.
  2. Watch the status under the box — it checks your JSON as you type and points to the first error.
  3. Press Format to beautify, Minify to compress, or Validate for a quick summary of what the JSON contains.
  4. Copy the result or download it as a .json file.

Common JSON mistakes it catches

  • Trailing commas like {"a": 1,} — allowed in JavaScript, not in JSON.
  • Single quotes or unquoted keys like {'name': 'Ali'} — JSON needs double quotes.
  • Comments (// or /* */), undefined, NaN and Python-style True/None.
  • Curly quotes pasted from WhatsApp, Word or Google Docs instead of straight " quotes.
  • Missing commas and unclosed brackets, with the line where the bracket was opened.

Why the output matches your input exactly

Many formatters run your JSON through JSON.parse and back, which silently rounds integers larger than 9,007,199,254,740,991 and drops duplicate keys. This tool re-indents the original text instead, so values come out exactly as they went in.

Private by design. Everything runs in your browser — nothing you enter is uploaded or stored by AISeekho.

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