100% Client-side · Your JSON never leaves your browser
Validate JSON with Human-Readable Errors
Catch syntax errors with plain-English explanations and contextual fix suggestions. Smarter than your IDE.
JSON Tools
Choose your method.
Beautify — pretty-print with 2-space indentation. Cmd+Enter to run
Input 0 chars
Output
Mode
Indent
Paste JSON and it updates live.
Or press Cmd+Enter.
FAQ
JSON Validator — Frequently Asked Questions
How our JSON lint tool, JSON syntax checker and validator handle the edge cases.
How does this online JSON validator work?
Paste any JSON into the editor and the JSON syntax checker runs live as you type. Errors appear inline with the exact line and column, plus a plain-English explanation — no need to decode "Unexpected token at position N" yourself.
How is this JSON lint tool better than a standard parser?
Standard JSON parsers report a single byte offset. Our JSON lint tool translates parser errors into plain English and pinpoints the exact character. "Unexpected token } in JSON at position 47" becomes "Trailing comma before line 12 — JSON does not allow it."
Does the JSON checker send my JSON to a server?
No. The JSON validator runs entirely in your browser. We have no servers, no logs of your data, and no behavioural analytics on your inputs — your data never leaves your device.
Can the JSON validator auto-fix errors it finds?
Yes — switch to the Auto-Fix tab to repair trailing commas, single-quoted strings, unquoted keys, and JS-style comments. For pretty-printing without edits, use the JSON Formatter.
Why does it show fix suggestions, not just errors?
Most JSON errors are typos. We pattern-match the error and offer the most likely fix — saving you the round-trip to Stack Overflow. Suggestions are non-destructive: you decide whether to accept them.
Does this JSON validator support JSON5 / JSONC?
Strict validation rejects comments and trailing commas (per the JSON spec). Switch to Auto-Fix to accept JSON5 / JSONC inputs — comments are stripped, trailing commas removed, and unquoted keys quoted automatically.
What is a "valid JSON formatter"?
A valid JSON formatter validates first, then formats — guaranteeing the output is parseable JSON. This page does both: it runs as a strict JSON checker before pretty-printing, so you never get malformed output.