Free online JSON fixer. Auto-repair common JSON errors: trailing commas, single quotes, comments, unquoted keys, Python booleans. Runs locally in your browser, no data uploaded.
100% Local
How to Use the JSON Fixer
Paste broken or non-standard JSON into the input box. Click Fix JSON and the tool automatically repairs common syntax errors, then pretty-prints the result. Use Clear to reset both panels.
Errors the fixer repairs
Removes single-line // and multi-line /* */ comments
Strips trailing commas before closing brackets or braces
Converts single-quoted strings to double-quoted strings
Adds quotes around unquoted object keys like {name: "x"}
Converts Python-style True, False, None to true, false, null
Features
Applies all fixes in one pass — no manual steps
Still-valid JSON is left untouched
Reports remaining errors if the fix is incomplete
All processing runs locally in your browser. Your data is not uploaded to any server.