JSON Auto-Repair
Parses broken JSON character by character (not with unsafe regex substitutions) to fix common mistakes that have exactly one correct interpretation: trailing commas before a closing bracket, unquoted object keys, single-quoted strings, comments (not valid in JSON), and a missing comma between two consecutive items. Every change made is shown clearly, and genuinely ambiguous cases are never guessed at — if a full repair isn't possible, the tool says so instead of silently changing your data in a way that might be wrong. Everything happens in your browser, with nothing ever uploaded to a server.
Text is processed entirely on your device and is never sent to a server.
Result
The result will appear here after clicking "Repair JSON"
What this tool does
Fixes the common JSON errors that have exactly one unambiguous correct reading: trailing commas, unquoted keys, single-quoted strings, comments, and a missing comma between two members — and tells you precisely what it changed.
When to use it
- You copied an object out of JavaScript source and its keys are unquoted.
- A config file contains comments that stop it parsing as JSON.
- JSON produced by a language model has a trailing comma on the last item.
- Data copied from a source that uses single quotes.
How to use it
- Paste the text into the "Broken JSON" field.
- Click "Repair JSON".
- Review the "Changes made" list to see exactly what was addressed.
- Copy the result if it came back valid.
A practical example
Input
{name: 'Uddatak', active: true,}
Output
{"name": "Uddatak", "active": true} with the changes listed as an unquoted key, a single-quoted string and a trailing comma.
Limitations
- It does not guess: anything structurally ambiguous — a genuinely malformed escape sequence, say — is left alone, and you are told plainly that the repair is incomplete.
- Text that was already valid comes back unchanged with a message saying there was nothing to repair.
- It repairs syntax, not meaning; wrong data stays wrong once its structure is fixed.
Privacy and processing
The text is processed entirely on your device and is never sent to a server.
Technical notes
- Repair works by tokenising and rebuilding the text rather than by regex substitution — because a regular expression cannot tell a comma inside a string from a genuine trailing comma, or a "//" inside a URL from a real comment.
- One parse state is tracked per open container, which is what makes the repair reliable inside nested structures.
Frequently Asked Questions
No — it only fixes cases with exactly one unambiguous interpretation (like a trailing comma or an unquoted key). If an error is ambiguous enough to have more than one possible fix, the tool leaves it alone rather than guessing.