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"JSON Repair":{ }

Paste broken, truncated, or non-standard JSON and get strictly-valid JSON back. Fixes single quotes, trailing commas, comments, unquoted keys, Python-style literals, and missing brackets, then pretty-prints the result. Runs 100% in your browser: zero network requests, so your data never leaves the page.

What is a JSON repair tool?

A JSON repair tool (or JSON fixer) takes malformed JSON and rewrites it into strictly-valid JSON. Real-world JSON is often broken: copied from a Python dict, hand-edited with a stray comma, generated by an LLM that added comments, or truncated by a log limit. Instead of hunting for the bad character by hand, paste it here and get a clean, parseable result, formatted and ready to use. It all runs in your browser, so even payloads with secrets stay on your machine.

Repair vs. validate

These are opposite jobs. Repair rewrites non-standard input into valid JSON. Use it to fix and move on. The JSON Validator is strict on purpose: it tells you exactly where and why JSON is invalid without changing it. Use it to catch problems before shipping. A common flow is to validate, see the error, then repair.

How to use

  1. Paste broken, truncated, or non-standard JSON into the Input pane.
  2. The repaired, strictly-valid JSON appears instantly in the Output pane, pretty-printed.
  3. Common problems are fixed automatically: single quotes, trailing commas, comments, unquoted keys, Python-style True/False/None, and missing brackets.
  4. Copy the fixed JSON; it passes JSON.parse and strict validators.
  5. Runs 100% in your browser; nothing is uploaded.

Examples

Single quotes + trailing comma + Python literals

Input
{ 'name': 'api', 'active': True, 'tags': ['a', 'b',], }
Output
{
  "name": "api",
  "active": true,
  "tags": [
    "a",
    "b"
  ]
}

Unquoted keys and comments

Input
{
  // config
  id: 42,
  name: workbench
}
Output
{
  "id": 42,
  "name": "workbench"
}

Truncated / missing brackets closed

Input
{"a":1,"b":[1,2,3
Output
{
  "a": 1,
  "b": [
    1,
    2,
    3
  ]
}

FAQ

What does the JSON repair tool fix?

Single quotes → double quotes, unquoted object keys, trailing commas, // and /* */ comments, Python-style True/False/None, smart/curly quotes, and missing or unbalanced brackets and braces. It reconstructs the most likely valid JSON and pretty-prints it.

How do I fix "Unexpected end of JSON input"?

That error means the JSON is truncated: a bracket or quote is never closed. Paste it here and the repairer closes the open structures to produce valid JSON. Then check the result matches what you expected.

Is the repaired JSON guaranteed correct?

It's guaranteed to be valid JSON (it parses). Because repair infers intent, always sanity-check the output for badly truncated or ambiguous input; the tool picks the most likely fix, not necessarily the one you meant.

Does it work on LLM / ChatGPT output?

Yes. Model output often has trailing commas, comments, or gets cut off mid-response, all common repair cases. Paste it and get clean JSON back.

Is my data uploaded?

No. Repair runs entirely in your browser. Open DevTools → Network: zero requests after load. Nothing is stored.

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