JSON Repair
Repair broken or invalid JSON in your browser. Fix trailing commas, single quotes, unquoted keys, missing brackets, comments, and Python constants, then copy or download valid JSON without uploading your data.
Key Features
Fix Common JSON Errors
Repair JSON with trailing commas, single quotes instead of double quotes, unquoted object keys, and missing closing brackets. The tool applies best-effort fixes and returns valid JSON when the structure can be recovered.
Strip JSON Comments
Remove single-line (//) and block (/* */) comments from JSON-like input. Comments are not valid standard JSON, so they are stripped before the result is serialized.
Normalize Quotes
Convert single quotes to double quotes and normalize smart quotes (“ ” ‘ ’) to straight quotes. Unquoted object keys are wrapped in double quotes so the document parses.
Handle Python and JS Constants
Convert Python constants such as True, False, and None, plus common JavaScript values such as NaN and Infinity, into valid JSON values when they appear in the input.
Validate After Repair
The repaired output is parsed to confirm it is valid JSON before it is shown. If the document cannot be recovered, the tool reports an error instead of returning a partial or misleading result.
Copy or Download
Copy the repaired JSON to your clipboard or download it as a .json file for use in APIs, configuration, tests, or other development workflows.
Paste or Open JSON
Paste broken JSON into the input or open a local file. The repair runs in your browser, so the source text is not uploaded to a server.
Browser-Based Processing
Repair, validation, and formatting happen in your browser. The page does not require an account or send your JSON to a remote service.
How to Use
Paste broken JSON
Paste invalid JSON into the input field, or open a local .json file. The page accepts documents with trailing commas, single quotes, unquoted keys, comments, or missing brackets.
Repair the input
Click Repair JSON. The tool attempts best-effort fixes and parses the result. If the document can be recovered, valid JSON is produced; otherwise an error is reported.
Review the valid output
Check the repaired JSON in the output panel. Use the indent selector to switch between 2 spaces, 4 spaces, or a tab for the displayed result.
Copy or download
Copy the repaired JSON or download it as a .json file. Validate it with a JSON schema validator before using it in production if the data is important.
JSON Repair Example
Recover an invalid JSON document that uses comments, single quotes, unquoted keys, and a trailing comma.
// user record
{
name: 'Alice',
age: 28,
active: True,
tags: ['admin', 'user',],
}This document is not valid JSON: it has a // comment, single-quoted strings, an unquoted key, a Python True, and a trailing comma before the closing bracket.
{
"name": "Alice",
"age": 28,
"active": true,
"tags": [
"admin",
"user"
]
}The repair strips the comment, converts quotes and the key, maps True to true, removes the trailing comma, and produces valid, parseable JSON.
Repair is best-effort. It cannot invent missing data, so a document that is too structurally broken may still fail to repair.
How to Repair Invalid JSON Online
What Is JSON Repair?
JSON repair is the process of turning invalid JSON into valid, parseable JSON. Real-world JSON often breaks because of copy-paste from code, exported configuration, or REPL output. A JSON fixer applies best-effort corrections so the document can be parsed again.
Common JSON Errors This Tool Fixes
- Trailing commas: a comma before a closing
}or]is removed. - Single quotes: strings written with single quotes are converted to double quotes.
- Unquoted keys: object keys without quotes are wrapped in double quotes.
- Missing brackets: unclosed
{or[are closed when the structure allows it. - Comments:
//and/* */comments are stripped. - Python and JS constants:
True,False,None,NaN, andInfinityare mapped to valid JSON.
How to Repair Broken JSON
- Paste the broken JSON: include comments, single quotes, or trailing commas if present.
- Repair: the tool applies fixes and parses the result.
- Review: confirm the output is valid JSON and adjust the indent if needed.
- Copy or download: use the repaired document in your workflow.
Repair vs Format
Repair fixes syntax so the document becomes valid JSON. Formatting, by contrast, only changes indentation and spacing of JSON that is already valid. Use repair first; if you only need readable spacing on valid JSON, a formatter is enough.
Limits of JSON Repair
JSON syntax error fix is best-effort. It cannot invent missing data or recover a document whose structure is fundamentally wrong. If the input is too broken, the tool reports an error rather than returning a misleading result. After repair, validate important data with a JSON schema validator before using it in production.
Privacy
Repair runs entirely in your browser. Your JSON is not uploaded, and no account is required. Do not paste passwords, tokens, or production credentials into any online tool.
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