UUID Generator — Developer Code Samples

UUIDs (Universally Unique Identifiers) are 128-bit identifiers with an astronomically low collision probability. UUID v4 is random, v1 is time-based, and v5 is name-based with SHA-1 hashing. Python's uuid module and Node's crypto module generate them natively.

Try the interactive version online: Open UUID Generator Tool →

Parameters

Parameter	Type	Required	Description
version	int	No	UUID version: 1 (time-based), 4 (random), 5 (name-based) (default: 4)
namespace	str	No	For v5: namespace UUID (e.g., uuid.NAMESPACE_DNS)
name	str	No	For v5: name string to hash into UUID

Returns: UUID string in standard format: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

Code Examples

import uuid

# Generate a random UUID v4 (most common)
uid = uuid.uuid4()
print(uid)
# Output: 550e8400-e29b-41d4-a716-446655440000 (random each time)

# UUID as string
uid_str = str(uuid.uuid4())
print(uid_str)

# UUID without hyphens (used in some databases)
uid_clean = uuid.uuid4().hex
print(uid_clean)
# Output: 550e8400e29b41d4a716446655440000

# UUID v1 (time-based, includes MAC address)
uid_v1 = uuid.uuid1()
print(f"v1: {uid_v1}")

# UUID v5 (name-based, deterministic)
namespace = uuid.NAMESPACE_DNS
uid_v5 = uuid.uuid5(namespace, "example.com")
print(f"v5: {uid_v5}")  # Always the same for same input

# Generate multiple UUIDs
uuids = [str(uuid.uuid4()) for _ in range(5)]
for u in uuids:
    print(u)

# Validate a UUID string
def is_valid_uuid(val):
    try:
        uuid.UUID(str(val))
        return True
    except ValueError:
        return False

print(is_valid_uuid("550e8400-e29b-41d4-a716-446655440000"))  # True
print(is_valid_uuid("not-a-uuid"))  # False

// Node.js: built-in crypto (Node 15+)
const { randomUUID } = require('crypto');
const uid = randomUUID();
console.log(uid);
// Output: 9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d

// UUID without hyphens
const uidClean = randomUUID().replace(/-/g, '');
console.log(uidClean);

// Browser: crypto.randomUUID() (modern browsers)
const browserUUID = crypto.randomUUID();
console.log(browserUUID);

// Custom UUID v4 implementation (fallback)
function generateUUIDv4() {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
    const r = Math.random() * 16 | 0;
    const v = c === 'x' ? r : (r & 0x3 | 0x8);
    return v.toString(16);
  });
}

// Generate multiple UUIDs
const uuids = Array.from({ length: 5 }, () => randomUUID());
console.log(uuids);

// Validate UUID format
function isValidUUID(str) {
  return /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(str);
}

# Generate UUID v4 (Linux/Mac)
uuidgen

# Generate UUID v4 lowercase
uuidgen | tr '[:upper:]' '[:lower:]'

# UUID without hyphens
uuidgen | tr -d '-'

# Generate 5 UUIDs
for i in {1..5}; do uuidgen; done

# With Python (cross-platform)
python3 -c "import uuid; print(uuid.uuid4())"

# UUID v5 (deterministic from name)
python3 -c "import uuid; print(uuid.uuid5(uuid.NAMESPACE_DNS, 'example.com'))"

# Use in a shell script variable
MY_ID=$(uuidgen | tr '[:upper:]' '[:lower:]')
echo "Generated ID: $MY_ID"

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