UUID Regex Pattern API: Validate UUID/GUID Formats

Need to validate UUID strings in your application? This guide covers the UUID Regex Pattern API, which provides patterns for validating UUID formats, detecting UUID versions, and handling various formatting styles like with or without dashes.

UUID Format Structure

A UUID (Universally Unique Identifier) is a 128-bit identifier typically represented as 32 hexadecimal digits in the format:

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx

Where M indicates the version and N indicates the variant. For example: 550e8400-e29b-41d4-a716-446655440000

UUID Versions

The version digit (M) indicates how the UUID was generated:

• Version 1: Time-based UUID (starts with 1 in position 13)
• Version 3: Name-based using MD5 hash
• Version 4: Random UUID (most common, starts with 4)
• Version 5: Name-based using SHA-1 hash

Using the UUID Regex API

TinyFn provides UUID validation patterns:

GET https://api.tinyfn.io/v1/regex/patterns/uuid
Headers: X-API-Key: your-api-key

{
  "pattern": "^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$",
  "type": "any",
  "description": "Validates any valid UUID (v1-v5)",
  "flags": "i",
  "examples": {
    "valid": ["550e8400-e29b-41d4-a716-446655440000", "6ba7b810-9dad-11d1-80b4-00c04fd430c8"],
    "invalid": ["not-a-uuid", "550e8400-e29b-61d4-a716-446655440000"]
  }
}

Parameters

Code Examples

JavaScript / Node.js

// Get UUID v4 specific pattern
const response = await fetch(
  'https://api.tinyfn.io/v1/regex/patterns/uuid?version=4',
  { headers: { 'X-API-Key': 'your-api-key' } }
);
const { pattern, flags } = await response.json();

// Validate UUIDs
const uuidRegex = new RegExp(pattern, flags);
console.log(uuidRegex.test('f47ac10b-58cc-4372-a567-0e02b2c3d479')); // true (v4)
console.log(uuidRegex.test('6ba7b810-9dad-11d1-80b4-00c04fd430c8')); // false (v1)

Python

import requests
import re

response = requests.get(
    'https://api.tinyfn.io/v1/regex/patterns/uuid',
    params={'allow_no_dashes': 'true'},
    headers={'X-API-Key': 'your-api-key'}
)
pattern = response.json()['pattern']

uuid_pattern = re.compile(pattern, re.IGNORECASE)

# Both formats will match
print(bool(uuid_pattern.match('550e8400-e29b-41d4-a716-446655440000')))  # True
print(bool(uuid_pattern.match('550e8400e29b41d4a716446655440000')))  # True

cURL

curl "https://api.tinyfn.io/v1/regex/patterns/uuid?version=4&case_sensitive=true" \
  -H "X-API-Key: your-api-key"

Common Use Cases

• API Validation: Validate UUID parameters in API requests
• Database IDs: Validate primary keys before database operations
• Form Validation: Validate UUID inputs in forms
• URL Routing: Match UUID patterns in URL paths
• Data Migration: Validate UUIDs during data import

Best Practices

1. Case insensitive: UUIDs are typically case-insensitive; allow both cases
2. Normalize format: Convert to lowercase with dashes for storage
3. Version validation: Only validate specific versions if your system requires it
4. Handle nil UUID: Decide if 00000000-0000-0000-0000-000000000000 is valid for your use case

Use via MCP

Your AI agent can call this tool directly via Model Context Protocol — no HTTP code needed. Add TinyFn to Claude Desktop, Cursor, or any MCP client:

{
  "mcpServers": {
    "tinyfn-regex": {
      "url": "https://api.tinyfn.io/mcp/regex/",
      "headers": {
        "X-API-Key": "your-api-key"
      }
    }
  }
}

See all regex tools available via MCP in our Regex MCP Tools for AI Agents guide.