Validate JSON instantly and pinpoint syntax errors with line, column and context details.
Paste or type some JSON to begin
Press Validate (or Ctrl+Enter) to check it. Live validation updates automatically after you stop typing.
This tool runs directly in your browser. The content you enter is processed locally and is not sent to TechFixGen servers. No account or signup is required.
A JSON validator checks whether text follows the JSON syntax rules and reports exactly where parsing fails. It answers one question: is this valid JSON — and if not, why not?
Validation happens entirely in your browser. When the input is invalid, the tool shows the error message, the line and column, the character index, a snippet of the surrounding text, and a plain explanation of the common mistake behind it.
Most invalid JSON fails for a handful of reasons. The validator recognises these automatically:
Missing comma
Two object properties or array items are written one after another without a separator.
Fix: Insert a comma between them: {"a":1,"b":2}.
Trailing comma
A comma sits immediately before a closing } or ], which JSON does not allow.
Fix: Remove the final comma: {"a":1} is valid, {"a":1,} is not.
Single quotes
Strings are wrapped in single quotes like 'name'. JSON only accepts double quotes.
Fix: Use double quotes: {"name":"Ada"}.
Unquoted keys
A property name is written bare, such as {name:"Ada"}.
Fix: Always quote property names: {"name":"Ada"}.
Mismatched braces or brackets
An object or array is closed with the wrong character, or a closer has no opener.
Fix: Pair every { with } and every [ with ], ensuring nesting order is preserved.
Invalid escapes
A backslash in a string starts an escape JSON does not recognise, such as \x.
Fix: Use only JSON escapes: \" \\ \/ \b \f \n \r \t or \uXXXX.
The JSON Validator answers whether your data is syntactically valid and pinpoints the first error when it is not. It does not change your data.
The JSON Formatter answers how it looks — it takes valid JSON and rewrites its presentation, beautifying it with indentation or minifying it down to one line. Formatting never repairs invalid JSON.
Use them together: validate first to confirm the document parses, then beautify the confirmed result on the formatter page.
Validation runs locally in your browser. The JSON you paste is never uploaded to TechFixGen servers and is not included in analytics events — no account or signup is required.
JSON fails validation when the text does not follow the JSON grammar — for example a missing comma, an unquoted property name, single quotes instead of double quotes, a trailing comma, an invalid escape sequence, or a missing closing brace or bracket. The validator reports the first error it finds with its line, column, and a snippet of surrounding text.
No. JSON does not allow a comma immediately before a closing } or ]. A document such as {"a":1,} is invalid. Remove the final comma.
No. Strings and property names in JSON must be wrapped in double quotes. Inputs like {'name':'Ada'} are invalid and will be flagged.
Yes. Every object property name must be a string in double quotes, so {name:"Ada"} is invalid while {"name":"Ada"} parses correctly.
No. Validation runs entirely in your browser. Your JSON is not uploaded to TechFixGen servers and is not included in analytics events.
Validation checks whether text is syntactically valid JSON and reports where it breaks. Formatting takes valid JSON and changes its presentation — beautifying it with indentation or minifying it. Use the JSON Validator to confirm a document parses, then the JSON Formatter to beautify the confirmed result.
No. The validator explains the error and suggests a fix, but it never rewrites your data. Correcting the input by hand is the safe, predictable way to resolve syntax issues.