JSON Validator
Validate JSON and find the exact error
Check JSON syntax instantly. Invalid JSON is underlined in red at the precise line and column, with a plain-English reason and a one-click fix — nothing leaves your browser.
🔒 100% private — your document is processed entirely in your browser and is never uploaded, logged, or stored.
Stop guessing where your JSON breaks
A validator that only says “Invalid JSON” wastes your time. Indentioshows the exact character where parsing failed, names the cause — a trailing comma, a single quote, an unclosed bracket — and suggests how to fix it. Valid JSON gets a clear green status.
What “valid JSON” means
Valid JSON follows a strict grammar: double-quoted keys and strings, no trailing commas, no comments, and exactly one top-level value. These rules make JSON portable across every language — and they’re exactly what this validator enforces.
Validate, then fix
- Live validation as you type, with a status of Valid or the first error’s location.
- Hover any red underline for the reason and a targeted hint.
- Click Auto-fix to repair common issues, or Format to beautify once valid.
Frequently asked questions
How do I check if my JSON is valid?
Paste it into the editor. Validation runs automatically as you type: a green status means valid JSON, and any error is underlined in red with its exact line and column.
What does the validator check?
It checks JSON syntax against the specification — quoting, commas, brackets, braces, and value types — and reports the first problem with a precise location and a fix suggestion.
Why does it say “trailing comma”?
JSON, unlike JavaScript, does not allow a comma after the last item in an array or object. The validator points at the exact comma so you can remove it — or click Auto-fix.
Does it store the JSON I paste?
No. Validation happens entirely in your browser; nothing is uploaded or saved.