🔍Regex Recipes

IPv6 Address (Basic)

Basic IPv6 address validation with common format support and important caveats.

Pattern

^(([0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}|::([0-9a-fA-F]{1,4}:){0,6}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:)$

Explanation

Basic IPv6 validation covering common formats. Full IPv6 validation is complex; consider using libraries.

Examples

Full format

Input

2001:0db8:85a3:0000:0000:8a2e:0370:7334

Output

✓ Match

Compressed

Input

2001:db8:85a3::8a2e:370:7334

Output

✓ Match

Loopback

Input

::1

Output

✓ Match

IPv4-mapped

Input

::ffff:192.168.1.1

Output

✗ No match (not covered)

Code Examples

JavaScript

// For production, use a library
function isValidIPv6(ip) {
  try {
    const url = new URL(`http://[${ip}]`);
    return true;
  } catch {
    return false;
  }
}

Try it Now

Open in Regex Tester

💡 Tips

Use ipaddress library (Python) or similar
IPv6 has many valid formats due to compression
Consider zone identifiers (%interface)
Test with real IPv6 addresses from your use case

⚠️ Common Pitfalls

IPv6 validation is extremely complex
Does not handle all compression formats
Does not validate IPv4-mapped IPv6 addresses
Strongly recommend using IP address libraries