JSON Validator. Line by line.
Check whether JSON is valid and get the exact line, column and snippet where parsing failed.
Paste some JSON and it will be checked as you type.
How to use JSON Validator
Paste the JSON you are debugging
A failing API response, a hand-edited config file or a payload copied out of a log — anything you need to check.
See exactly where it breaks
Instead of a bare 'Unexpected token', you get the line and column number, the offending snippet with a caret under the character, and a plain-English explanation of the likely cause.
Fix it and re-check
Correct the input and validation re-runs as you type. Once it is valid you get a summary of the parsed structure.
Why use Parsefy JSON Validator?
Your data never leaves your device
Everything runs in your browser tab — there is no upload step and no server to store anything. That makes it safe for API responses, database dumps and production data you could not paste into a hosted converter.
Errors you can act on
Browsers report a character offset that is useless in a 4,000-line file. Parsefy converts it to a line and column, shows the surrounding text and names the likely cause.
Catches the classic gotchas
Trailing commas, single quotes, smart quotes pasted from a document, unquoted keys and a stray byte-order mark are all called out by name instead of leaving you guessing.
No sign-up, no file-size tier
There is no account, no email wall and no paid plan gating bigger files. The only real limit is how much memory your own browser can spare.
JSON Validator — frequently asked questions
What does "Unexpected token" actually mean?
The parser reached a character that cannot legally appear at that point in the document. It is not telling you the character is wrong, only that it did not fit the structure — the real mistake is often slightly earlier, such as a missing comma on the previous line. That is why this tool shows the surrounding snippet rather than just the message.
Why does my JSON fail when it looks fine?
The usual suspects are invisible or easy to skim past: a trailing comma after the last array item, single quotes instead of double quotes, unquoted property names, curly smart quotes pasted from a document or chat app, or an invisible byte-order mark at the very start of the file. Parsefy flags each of these by name when it detects them.
Does this validate against a JSON Schema?
No — this checks syntax, not shape. It tells you whether the document is parseable JSON, not whether it matches a contract with required fields and types. For contract validation you want a JSON Schema validator; use this first to confirm the document parses at all.
Is my JSON sent to a server to be validated?
No. Validation uses your browser's own JSON parser and never leaves the tab, so you can safely check payloads containing credentials, tokens or customer data.