jsonfix

A CLI tool that fixes common JSON issues. No more hand-editing broken JSON from config files, API responses, logs, or copy-pasted snippets.

What it fixes

• Trailing commas — {"a": 1, "b": 2,} becomes valid
• Single quotes — {'key': 'value'} converted to double quotes
• Comments — // line and /* block */ comments stripped
• Unquoted keys — {name: "val"} gets proper key quoting
• Missing closing brackets — best-effort bracket completion

Install

npm install -g jsonfix-cli

Or use without installing:

npx jsonfix-cli broken.json

Usage

Fix a file

jsonfix broken.json

Pipe from stdin

echo "{ name: 'test', }" | jsonfix

cat config.jsonc | jsonfix

Write output to a file

jsonfix broken.json -o fixed.json

Check if JSON is valid (no output, exit code only)

jsonfix --check config.json
# Exit code 0 = valid, 1 = invalid

Minify output

jsonfix data.json --minify

Custom indentation

jsonfix data.json --indent 4

Combine flags

cat api-response.txt | jsonfix --indent 4 -o clean.json

Flags

| Flag | Short | Description | Default | |------|-------|-------------|---------| | --output <file> | -o | Write output to a file instead of stdout | — | | --check | -c | Validate only; exit 0 if valid, 1 if not | false | | --minify | -m | Minify the output (no whitespace) | false | | --indent <n> | -i | Number of spaces for indentation | 2 | | --help | -h | Show help message | — | | --version | -v | Show version number | — |

Exit codes

| Code | Meaning | |------|---------| | 0 | Success (or valid JSON with --check) | | 1 | Invalid JSON that could not be fixed (or invalid with --check) | | 2 | File not found or I/O error |

Examples

Input:

{
  // Database config
  host: 'localhost',
  port: 5432,
  options: {
    ssl: true,
    timeout: 30, /* seconds */
  },
}

Output:

{
  "host": "localhost",
  "port": 5432,
  "options": {
    "ssl": true,
    "timeout": 30
  }
}

Zero dependencies

jsonfix uses only Node.js built-in modules. Nothing extra to install, audit, or worry about.

License

MIT