Broken JSON is usually someone's hand-typed data: a missing quote, a forgotten comma, a bracket that never got closed. Most tools tell you it's invalid and stop there. A JSON repair tool actually fixes it. Here are the common cases and how JSONGuy handles them.

Missing quotes

Unquoted keys and string values are the most common mistake:

{
  name: John,
  city: New York
}

Becomes:

{
  "name": "John",
  "city": "New York"
}

Missing commas

When you copy fields around, the commas often get lost:

{
  "name": "John"
  "age": 30
}

Repaired:

{
  "name": "John",
  "age": 30
}

Unclosed brackets

Truncated output is a classic — the log got cut off mid-array:

{
  "tags": ["dev", "ops"
}

The missing brackets are added to close the structure:

{
  "tags": ["dev", "ops"]
}

Single quotes, trailing commas, comments

JSON only allows double quotes and no trailing commas, but plenty of real input uses single quotes, leaves a trailing comma, or carries a comment:

{
  'name': 'John', // hand-written
  'active': true,
}

All of it is normalized into strict JSON automatically.

Python syntax

Paste a Python dict with None, True, and tuples, and they're converted too:

{
  'active': True,
  'nickname': None,
  'tags': ('a', 'b'),
}

Try it

Paste anything broken into the JSON repair tool and it comes back as valid JSON — in your browser, nothing uploaded. If the input is already fine, it just formats it and tells you.