A .NET regular expression for extracting a single root-level JSON block from text.

Supports:

• Root objects { ... }
• Root arrays [ ... ]
• Nested objects and arrays
• Escaped quotes inside strings
• Single-line comments // ...
• Multi-line comments /* ... */

This regex performs structural matching only. It validates balanced braces/brackets and ignores delimiters inside strings and comments.

Features

• Captures the JSON block in the json group.
• Allows comments and whitespace before and after the JSON block.
• Uses .NET balancing groups for nested structures.
• Designed as a first parsing stage before actual JSON deserialization.

Limitations

This is not a full JSON parser.

It does not validate:

• JSON syntax rules
• Property names
• Value types
• Duplicate keys
• Commas and separators

Use a real JSON parser after extracting the block.

Compatibility

Requires a regex engine with balancing group support:

• ✅ .NET System.Text.RegularExpressions
• ❌ JavaScript RegExp
• ❌ Python re
• ❌ RE2

Example

Input:

// config
{
    "name": "example",
    "items": [
        1,
        2
    ]
}

Results:

Groups["json"] -> { "name": "example", "items": [1, 2] }