JSONValidator • Fixer • FormatterDiff • Undo

JSON Validator, Auto-Fixer & Formatter

Paste or upload any JSON dump. Detect problems, Fix with one click, compare changes in a side-by-side diff, undo fixes anytime, and export Human-Readable, Beautiful (sorted keys), or Compact JSON.

Client-side only JSONC tolerant One-click Fix

Input JSON

Upload

Paste your JSON (drag & drop file supported)

Indent

0 = single line (minified)

Sort Keys

Alphabetical (deep)

Undo Limit

Max undo steps

Validator & Auto-Fix

Valid JSON.

Detected issues

Trailing comma(s)
Remove trailing commas
Fix

Human Readable

null

Beautiful (sorted keys)

null

Compact (minified)

null

Size & Savings

Input

0 B

Readable

4 B

Δ 0%

Beautiful

4 B

sorted keys

Compact

4 B

Δ 0%

Tips

• Validator catches log/config issues (comments, trailing commas, smart quotes, unquoted keys, missing braces, noise).
• Fixer offers one-click auto-fix or granular fixes with a checklist.
• Diff shows a quick line-level comparison — and you can Revert Fix anytime.
• Formatter outputs Human-Readable, Beautiful (deep key sort), and Compact JSON.
• 100% client-side. For huge inputs, try the Compact output to reduce memory.

Quick Download

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