What types of JSON syntax errors can this tool repair?

JSON Repair fixes trailing commas, unquoted object keys, single quotes, unescaped line breaks, single-line and multi-line comments, and Python literals (True/False/None).

Why does standard JSON.parse() fail on my JSON?

The strict RFC 8259 JSON standard prohibits trailing commas, unquoted property keys, single quotes, and comments. Many modern APIs or LLMs output loose JavaScript objects rather than strict JSON.

Can this tool convert Python dictionaries to JSON?

Yes. Python dictionaries often use single quotes and capitalized booleans (True, False, None). JSON Repair converts these into valid standard JSON primitives.

Is my JSON data uploaded to an external server?

No. The repair algorithm executes purely within your local browser JavaScript environment. Your data never touches a remote server.

Can I format the repaired JSON with custom indentation?

Yes. You can output formatted JSON with 2 spaces, 4 spaces, or minified compact output ready for production transfer.

JSON Repair & Fixer

Automatically repair invalid JSON, fix trailing commas, unquoted keys, and single quotes.

100% free
Private in browser
No signup
No watermarks

Input JSON (or malformed JS/Python object)

Indent:

Repaired JSON

Valid JSON

{
  "name": "Antigravity Studio",
  "version": 2.5,
  "isActive": true,
  "tags": [
    "developer",
    "tools",
    "productivity"
  ],
  "metadata": {
    "author": "TheToolss Team",
    "contributors": null
  }
}

Repairs Applied

✓Removed JavaScript comments (// and /* */)
✓Converted Python literals (True/False/None) to JSON primitives
✓Replaced single quotes with standard double quotes
✓Added double quotes around unquoted object keys
✓Removed illegal trailing commas before closing braces/brackets

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About JSON Repair & Fixer

Got a malformed JSON payload from an API, log file, or LLM output that refuses to parse? JSON Repair on TheToolss automatically fixes syntax errors that break standard parsers. It converts single quotes to valid double quotes, quotes naked object keys, strips illegal trailing commas, deletes JavaScript comments (// and /* */), converts Python True/False/None to standard JSON primitives, and balances unmatched braces. Safe, instant, and runs 100% in your browser without transmitting your data.

How to use JSON Repair & Fixer

Paste your broken, invalid, or malformed JSON into the input box.
Select your preferred indentation (2 spaces, 4 spaces, or compact minified).
View the automatically repaired valid JSON and the log of fixes applied.

Key features

Quotes naked or unquoted JavaScript object keys automatically
Converts single-quoted strings to compliant double-quoted JSON strings
Strips illegal trailing commas from arrays and object definitions
Removes single-line (//) and multi-line (/* */) comments
Translates Python dictionary literals (True, False, None) to standard JSON
100% client-side execution — sensitive payload data stays on your machine

Frequently asked questions

What types of JSON syntax errors can this tool repair?: JSON Repair fixes trailing commas, unquoted object keys, single quotes, unescaped line breaks, single-line and multi-line comments, and Python literals (True/False/None).
Why does standard JSON.parse() fail on my JSON?: The strict RFC 8259 JSON standard prohibits trailing commas, unquoted property keys, single quotes, and comments. Many modern APIs or LLMs output loose JavaScript objects rather than strict JSON.
Can this tool convert Python dictionaries to JSON?: Yes. Python dictionaries often use single quotes and capitalized booleans (True, False, None). JSON Repair converts these into valid standard JSON primitives.
Is my JSON data uploaded to an external server?: No. The repair algorithm executes purely within your local browser JavaScript environment. Your data never touches a remote server.
Can I format the repaired JSON with custom indentation?: Yes. You can output formatted JSON with 2 spaces, 4 spaces, or minified compact output ready for production transfer.