JSON Validator
This free online JSON validator tells you within milliseconds whether your JSON parses — and if it does not, exactly where it breaks.
How to use
- Paste the JSON you want to check into the editor below.
- A valid document shows its top-level type and size immediately; an invalid one shows the line and column of the error.
- Fix the reported character, paste again, and confirm the green result before shipping.
Frequently asked questions
What error details do I get for invalid JSON?
The parser message plus the line and column where parsing stopped — for example "line 4, column 3". That is the character the parser choked on; the actual mistake (usually a missing comma or quote) is often just before it, so read the preceding characters too.
Are comments, trailing commas or single quotes allowed?
No, deliberately. The validator enforces strict JSON exactly as production parsers do: no comments, no trailing commas, no single-quoted strings, no unquoted keys. Text that passes here will parse the same way in your backend, not just in a lenient editor.
Why does the reported column look wrong near emoji?
Positions follow the JavaScript string convention (UTF-16 code units). Ordinary Chinese, Japanese and Korean characters count as one unit each, but emoji composed of a surrogate pair count as two. The offset is still exactly what JSON.parse reports in your own code, so it stays consistent.
What does a valid result tell me?
Besides validity you get the top-level type at a glance: object with its key count, array with its element count, or a scalar such as a number or string — a quick shape check against your API contract without opening any tools.
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About this tool
This free online JSON validator tells you within milliseconds whether your JSON parses — and if it does not, exactly where it breaks. A missing comma after a nested object, a stray trailing comma at the end of an array, an unquoted key copied from JavaScript source code: these errors are invisible in a wall of minified text, so the validator reports the line and column of the failure together with the parser message, letting you jump straight to the offending character instead of hunting through thousands of characters by eye. Valid JSON gets a concise summary of its top-level type — object with key count, array with element count, or a scalar — so you can confirm the shape matches what your API contract expects before you ship. The check is strict JSON as defined by the standard: no comments, no trailing commas, no single quotes, which is precisely what real parsers enforce in production. Everything runs entirely in your browser: payloads with personal data, tokens or credentials are parsed locally on your own device and never uploaded, stored or logged. Paste the JSON below and know in one glance whether it is clean.