What is UUID Regex?

A UUID (Universally Unique Identifier) is a 128-bit identifier used to uniquely label data across systems. It’s typically represented as 32 hexadecimal characters split into 5 groups by hyphens, like:

123e4567-e89b-12d3-a456-426614174000

UUIDs are used in databases, APIs, microservices, IoT, and any context requiring global uniqueness.

UUID Regex Pattern in Python

To match a standard UUID format (v1–v5), use this regex pattern:

^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$

This pattern checks:

• 8 hexadecimal characters

• 4-digit version group (starting with 1–5)

• 4-digit variant group (starting with 8–b)

• Final 12 hex digits

How to Validate UUIDs Using Regex in Python

Here’s how to use the re module in Python to match valid UUIDs:

import re

def is_valid_uuid(uuid_str):
    pattern = re.compile(r'^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$')
    return bool(pattern.match(uuid_str))

# Example test
uuids = [
    "123e4567-e89b-12d3-a456-426614174000",  # Valid
    "123e4567e89b12d3a456426614174000",      # Invalid (no hyphens)
    "ZZZe4567-e89b-12d3-a456-426614174000"   # Invalid (non-hex)
]

for u in uuids:
    print(f"{u} -> {is_valid_uuid(u)}")

Matching UUIDs Without Hyphens

If you need to match UUIDs where hyphens have been removed—sometimes encountered in compact database keys or legacy systems—you can simply adjust the regex pattern. Instead of including hyphens as separators, look for a continuous string of 32 hexadecimal characters.

Here's how you can modify the pattern:

^[0-9a-fA-F]

This pattern matches UUIDs written as a single, uninterrupted 32-character hexadecimal string (e.g., 123e4567e89b12d3a456426614174000). It’s useful when handling non-standard formats or cleaning up user input before validation.

Be sure to pick the pattern that matches your data’s format—hyphenated or plain—depending on your application’s needs.

Use Cases

• API Resource Identification: Use UUIDs in REST endpoints or JSON payloads to reference records uniquely.

• Database Indexing: Use UUIDs as primary keys to prevent collision across distributed tables.

• Session Management: Validate UUID-based tokens for user sessions in secure applications.

• Form Submissions: Check if hidden fields in forms pass valid UUIDs.

• Combine with Password Regex Python Validator to secure user login data.

Pro Tips

• UUIDs can be lowercase or uppercase, and this pattern matches both.

• Use Python’s uuid module to generate and compare UUIDs, and validate format with this regex.

• This regex only checks the format, not the UUID’s randomness or version logic.

• Normalize UUIDs to lowercase using .lower() before storage for consistency.

• Combine with the Email Regex Python Validator or Phone Number Regex Python Validator for full form validation in Python apps.