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.
Input JSON
Validator & Auto-Fix
- Trailing comma(s)Remove trailing commas
Human Readable
Beautiful (sorted keys)
Compact (minified)
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.
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If you’re not in a position to support us, that’s okay. Postly will still be here for you. But if you are one of the few who can chip in, your support directly keeps these tools online for everyone else.