MAC Address (Colon-Separated, Case-Insensitive) Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching mac address (colon-separated, case-insensitive), ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# MAC Address (Colon-Separated, Case-Insensitive)
# ReDoS-safe | RegexVault — Web & Network > MAC Address

import re

mac_address_colonseparated_caseinsensitive_pattern = re.compile(r'^[0-9a-fA-F]{2}(?::[0-9a-fA-F]{2}){5}$')

def validate_mac_address_colonseparated_caseinsensitive(value: str) -> bool:
    return bool(mac_address_colonseparated_caseinsensitive_pattern.fullmatch(value))

# Example
print(validate_mac_address_colonseparated_caseinsensitive("00:1A:2B:3C:4D:5E"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > MAC Address category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Preferred for input validation where user-submitted MAC addresses may be in mixed case. Normalize to lowercase before storage.