GUID Generator
Generate GUIDs (also called UUIDs) v4 instantly. Perfect for unique identifiers in databases, APIs, distributed systems, and any application requiring unique IDs.
100% Client-Side Processing
GUIDs are generated entirely in your browser using cryptographic randomness. No data is sent to any server.
Generate 1 to 1000 GUIDs at once. Perfect for database seeding, batch processing, or testing.
Table of Contents
What is a GUID?
A **GUID (Globally Unique Identifier)**, also called a **UUID (Universally Unique Identifier)**, is a 128-bit identifier that's designed to be unique across time and space. GUIDs/UUIDs are standardized by RFC 4122 and are commonly used in distributed systems, databases, APIs, and applications where unique identifiers are required. GUID is Microsoft's name for the same standard as UUID.
GUIDs are typically represented as 32 hexadecimal digits displayed in five groups separated by hyphens, in the format: `xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`. For example: `550e8400-e29b-41d4-a716-446655440000`.
The probability of generating duplicate GUIDs is extremely low (approximately 1 in 2^122 for GUID v4), making them suitable for use as unique identifiers without coordination between different systems.
GUID / UUID Versions
There are several versions of GUIDs/UUIDs, each with different characteristics and use cases:
GUID v4 (Random GUID)
GUID v4 is the most commonly used version. It's generated using random or pseudo-random numbers, making it ideal for most applications where uniqueness is the primary concern.
Characteristics:
- Generated using random numbers
- No information about when or where it was created
- Extremely low collision probability
- Most widely used and recommended for general purposes
Use cases: Database primary keys, API identifiers, session IDs, transaction IDs, resource identifiers
GUID v1 (Time-based GUID)
GUID v1 incorporates the current timestamp and the machine's MAC address (or a random node ID), making it possible to extract the creation time from the GUID.
Characteristics:
- Includes timestamp information
- Can be sorted chronologically
- Contains MAC address (can be privacy concern)
- Less commonly used than v4
Use cases: Distributed systems requiring chronological ordering, logging systems
Other GUID Versions
Other GUID versions (v2, v3, v5, v6, v7, v8) exist but are less commonly used. Our generator focuses on GUID v4, which is the most widely adopted and recommended version for most use cases.
How it Works
Our GUID Generator uses cryptographic randomness to generate GUID v4 identifiers:
- Cryptographic Randomness: Uses the browser's `crypto.randomUUID()` API or `crypto.getRandomValues()` for secure random number generation
- GUID v4 Format: Generates GUIDs following the RFC 4122 specification for version 4
- Client-Side Generation: All GUIDs are generated entirely in your browser — no server requests
- Instant Generation: GUIDs are generated instantly without delays or waiting
- Batch Generation: Generate multiple GUIDs at once (up to 1000) for efficiency
- Copy Functionality: Copy individual GUIDs or all GUIDs to clipboard with one click
The generator automatically creates new GUIDs when you change the count, and provides easy copy functionality for integrating GUIDs into your projects.
Common Use Cases
- Database Primary Keys: Use GUIDs as primary keys in databases to avoid ID conflicts in distributed systems
- API Identifiers: Generate unique identifiers for API resources, endpoints, and requests
- Session Management: Create unique session IDs for user authentication and tracking
- Distributed Systems: Generate unique IDs across multiple services without coordination
- File Naming: Create unique filenames to avoid conflicts when storing files
- Transaction IDs: Generate unique transaction identifiers for payment systems and financial applications
- Testing & Development: Generate test data, mock IDs, and sample identifiers for development
- Database Seeding: Generate multiple GUIDs for populating databases with test data
- Resource Identifiers: Create unique identifiers for resources in REST APIs and web services
- Event Tracking: Generate unique event IDs for analytics and logging systems
Examples
Example 1: Database Primary Key
Use GUIDs as primary keys in your database tables:
CREATE TABLE users (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
username VARCHAR(50),
email VARCHAR(100)
);
-- Or insert with explicit GUID
INSERT INTO users (id, username, email) VALUES (
'550e8400-e29b-41d4-a716-446655440000',
'johndoe',
'john@example.com'
);Example 2: API Resource Identifier
Use GUIDs as resource identifiers in REST APIs:
GET /api/users/550e8400-e29b-41d4-a716-446655440000
POST /api/orders
{
"id": "7c9e6679-7425-40de-944b-e07fc1f90ae7",
"userId": "550e8400-e29b-41d4-a716-446655440000",
"total": 99.99
}Example 3: JavaScript/Node.js
Generate GUIDs in JavaScript applications:
// Using crypto.randomUUID() (Node.js 14.17+, modern browsers)
const guid = crypto.randomUUID();
console.log(guid); // e.g., "550e8400-e29b-41d4-a716-446655440000"
// Using in an object
const user = {
id: crypto.randomUUID(),
name: 'John Doe',
email: 'john@example.com'
};Example 4: Database Seeding
Generate multiple GUIDs for database seeding:
-- Generate 10 GUIDs for test users
INSERT INTO users (id, username, email) VALUES
('550e8400-e29b-41d4-a716-446655440000', 'user1', 'user1@example.com'),
('6ba7b810-9dad-11d1-80b4-00c04fd430c8', 'user2', 'user2@example.com'),
('6ba7b811-9dad-11d1-80b4-00c04fd430c8', 'user3', 'user3@example.com'),
-- ... more users
;Frequently Asked Questions
GUID v4 (version 4) is a randomly generated GUID. It's the most commonly used GUID version and is generated using random or pseudo-random numbers. GUID v4 doesn't contain any information about when or where it was created, making it ideal for most applications where uniqueness is the primary concern.
GUID v4 has an extremely low collision probability — approximately 1 in 2^122 (or about 1 in 5.3 × 10^36). This means the chance of generating duplicate GUIDs is negligible for practical purposes. Even if you generated 1 billion GUIDs per second, it would take approximately 85 years to have a 50% chance of generating one duplicate.
GUID v4 uses cryptographic randomness, making them suitable for use in security-sensitive applications. However, GUIDs themselves are not encrypted or hashed — they're just unique identifiers. Don't use GUIDs as security tokens or passwords. They're designed for uniqueness, not secrecy.
Yes! You can generate 1 to 1000 GUIDs at once. This is perfect for database seeding, batch processing, testing, or any scenario where you need multiple unique identifiers. Simply adjust the "Number of GUIDs" input and click generate.
No. All GUID generation happens entirely in your browser using the browser's cryptographic APIs. Your data is never sent to any server, ensuring complete privacy and security.
GUID v1: Time-based GUID that includes timestamp and MAC address information. Can be sorted chronologically but contains potentially sensitive information.
GUID v4: Randomly generated GUID with no embedded information. Most widely used, recommended for general purposes, and provides better privacy since it doesn't contain any identifying information.
GUID and UUID are effectively the same thing in practice: **GUID** is Microsoft's name for the same standard, while **UUID** is the standards-based name from RFC 4122.
Most "UUID generators" are just generating GUID v4 (random GUIDs) anyway. Both terms refer to the same 128-bit unique identifier format. The generator on this page produces standard GUID v4 values that work interchangeably as GUIDs or UUIDs in any system.
Yes! GUIDs are commonly used as primary keys in databases, especially in distributed systems. However, be aware that GUIDs are larger (16 bytes) than integer IDs (4-8 bytes) and may have performance implications for very large tables or indexes. Many databases have native GUID/UUID support with optimized storage.
GUIDs follow a specific format: 32 hexadecimal digits displayed in five groups separated by hyphens: `xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`. You can validate GUIDs using regular expressions or GUID validation libraries. Most programming languages have GUID validation functions in their standard libraries.
GUID v4 (random GUIDs) cannot be meaningfully sorted since they're randomly generated. GUID v1 (time-based GUIDs) can be sorted chronologically since they contain timestamp information. If you need sortable unique IDs, consider GUID v1 or using ULIDs (which are lexicographically sortable).
Modern browsers (Chrome 92+, Firefox 95+, Safari 15.4+, Edge 92+) support the native `crypto.randomUUID()` API. Our generator also includes a fallback method using `crypto.getRandomValues()` for older browsers, ensuring GUID generation works across all modern browsers.