URL with User Authentication Regex for Python

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching url with user authentication, 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

# URL with User Authentication
# ReDoS-safe | RegexVault — Web & Network > URL

import re

url_with_user_authentication_pattern = re.compile(r'^https?://[a-zA-Z0-9._~!$&'()*+,;=%-]+(?::[a-zA-Z0-9._~!$&'()*+,;=%-]*)?@(?:[a-zA-Z0-9\-]+\.)+[a-zA-Z]{2,63}(?::[1-9][0-9]{0,4})?(?:/[^\s]*)?$')

def validate_url_with_user_authentication(value: str) -> bool:
    return bool(url_with_user_authentication_pattern.fullmatch(value))

# Example
print(validate_url_with_user_authentication("http://user:password@example.com"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > URL 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

Embedding credentials in URLs is a significant security risk — they appear in browser history, server logs, and referrer headers. Use Authorization headers instead.