Free GUID & UUID Generator UUID Generator Online Free | GUID Generator v4
Generate UUID online free - instant random UUID v4 & GUID generator with bulk mode (up to 500 IDs). RFC 4122 compliant, cryptographically secure. Best UUID generator and GUID generator tool for developers 2026.
RFC 4122 v4
Bulk Mode
Generate UUID Online (v4 Generator Tool)
Uses `crypto.getRandomValues` for random byte generation in modern browsers.
Set options and click Generate UUIDs.
Quick start
How to Generate UUID v4 Online Free
Follow these straightforward steps to generate and export random identifiers instantly.
Choose a count between 1 and 500.
Set uppercase, no-hyphen, and brace options as needed.
Pick newline, comma+space, or semicolon+space separation.
Click Generate UUIDs to produce fresh random identifiers instantly.
Copy output to clipboard or export as a TXT file.
What is a UUID Generator?
Why use our UUID Generator?
- 100% free UUID generator online
- No data sent to server (secure)
- Bulk UUID generation up to 500
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit label used to identify information in computer systems. Standardized by RFC 4122, UUIDs guarantee uniqueness across space and time without requiring a central registration authority. They are widely used in real-world applications to uniquely identify records, users, and transactions. Using a reliable uuid generator online ensures these identifiers are created securely and efficiently.
UUIDs follow the standard defined in RFC 4122.
UUID Structure
A standard UUID is a 128-bit value represented as a 36-character string. This string consists of 32 hexadecimal digits separated by 4 hyphens in the format 8-4-4-4-12.
Sample UUID Output
550e8400-e29b-41d4-a716-446655440000
How long is a UUID?
A UUID is 128 bits long (16 bytes). When you generate UUID strings, the standard output contains 36 characters including hyphens.
UUID vs GUID
UUID and GUID are essentially the same. GUID is Microsoft's term, while UUID is the standardized name defined in RFC 4122.
Common Uses of UUID Generator
- Generate UUID for database primary keys
- Create unique IDs for APIs and microservices
- Generate random UUID for testing applications
- Use UUIDs for session tracking and logging
Generate UUID instantly using our free UUID generator above.
UUID v4 vs Other Versions
| Version | Description |
|---|---|
| v1 | Timestamp + MAC Address (can expose origin info). |
| v4 (This Tool) | Randomly generated (this tool). Safest for general use. |
| v7 | Time-ordered value (trending for database sorting). |
UUID vs ULID vs UUID v7
While UUID v4 is fully random, modern databases often benefit from sortable identifiers. UUID v7 and ULID (Universally Unique Lexicographically Sortable Identifier) incorporate a timestamp that allows database rows to be sorted chronologically while retaining uniqueness. If you need purely random, unguessable keys, use a UUID v4 generator. If you need index-friendly sorting, look into UUID v7 or a ULID generator.
Developer Section: Code Snippets
If you prefer not to use a web-based uuid v4 generator and need to generate UUIDs programmatically, here are quick snippets for popular languages:
JavaScript / Node.js
crypto.randomUUID();
Python
import uuid
print(uuid.uuid4())
UUID Validation Regex
Use this regular expression to strict-match a UUID v4 string:
^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$
You can also validate UUID formats using our regex tester.
🔑 Free UUID & GUID Generator - Trusted by 50K+ Developers
Generate random UUID v4 and GUID identifiers instantly. RFC 4122 compliant, cryptographically secure, with bulk generation up to 500 IDs. The best UUID generator online free tool for 2026.
⚡
Instant Generation
Generate 500 UUIDs in under 1 second
🔒
Cryptographically Secure
Uses crypto.getRandomValues API
📦
Bulk Mode
Up to 500 UUIDs per generation
✅ RFC 4122 v4 compliant | ✅ No server upload | ✅ Multiple formats | ✅ Copy & download | ✅ Works offline
GUID vs UUID
GUID Generator Online - What is GUID vs UUID?
Understanding the difference between GUID and UUID, when to use each term, and how to generate GUIDs for Microsoft development.
What is a GUID Generator?
A GUID generator (Globally Unique Identifier generator) creates unique 128-bit identifiers following the same format as UUIDs. GUID is Microsoft's terminology for UUID, primarily used in Windows development, COM programming, .NET applications, and Microsoft SQL Server databases.
When you use a GUID generator online, you're essentially using a UUID generator - the output is identical. The term "GUID" is more common in Microsoft ecosystems (C#, VB.NET, ASP.NET, SQL Server), while "UUID" is the universal standard term used in Python, Java, JavaScript, PostgreSQL, and RFC 4122 documentation.
Example GUID output: 550e8400-e29b-41d4-a716-446655440000
GUID vs UUID - Key Differences Explained
Short answer: GUID and UUID are the same thing. There's no technical difference - both are 128-bit unique identifiers with identical structure and generation algorithms.
The only difference is terminology:
- UUID (Universally Unique Identifier) - Universal standard defined in RFC 4122. Used by Python, Java, JavaScript, PostgreSQL, MongoDB, MySQL.
- GUID (Globally Unique Identifier) - Microsoft's name for the same concept. Used by C#, .NET, SQL Server, Windows COM, Active Directory.
When developers search for "guid generator" or "uuid generator", they're looking for the same tool. This generator produces both - call it whatever fits your technology stack. .NET developers might say "generate GUID", while Node.js developers say "generate UUID" - both get identical results.
How to Generate GUID for Microsoft Development
For Microsoft development, use this GUID generator online for:
- C# / .NET: Generate GUIDs for database primary keys, entity IDs, session tokens
- SQL Server: Create UNIQUEIDENTIFIER column values
- COM objects: Generate CLSIDs and IIDs for COM component registration
- Active Directory: Object GUIDs for AD entries
- Azure: Resource identifiers, subscription IDs, tenant IDs
- ASP.NET: User IDs, session IDs, request correlation IDs
C# equivalent: This online GUID generator produces the same output as System.Guid.NewGuid() in C#. Use bulk mode to generate hundreds of GUIDs for test data seeding, database migrations, or API testing.
Format options: Microsoft GUIDs are often displayed in braces {GUID} or uppercase. This generator supports both - enable "Wrap with braces" and "Uppercase output" for Microsoft-style GUID formatting.
Online GUID Generator vs Desktop Tools
Why use an online GUID generator instead of desktop tools or Visual Studio?
- ✅ No installation: Works instantly in any browser without downloading software
- ✅ Bulk generation: Create 500 GUIDs at once (faster than desktop guidgen.exe)
- ✅ Cross-platform: Works on Windows, Mac, Linux (guidgen.exe is Windows-only)
- ✅ Format options: Uppercase, lowercase, braces, no-hyphens in one tool
- ✅ Copy & download: One-click copy or download as TXT file
- ✅ Always available: Access from anywhere, no Visual Studio required
- ✅ Free forever: Unlimited GUID generation, no license costs
Desktop tools like Visual Studio's "Create GUID" or Windows guidgen.exe are fine for single GUIDs, but this online tool excels at bulk generation, format flexibility, and cross-platform availability. Generate hundreds of GUIDs for database seeding, test fixtures, or API mocking in seconds.
Bulk generation
Generate Random UUID - Bulk UUID Generator for Developers
How to generate random UUID v4 identifiers in bulk for testing, database seeding, API development, and microservices.
Random UUID Generator - When and Why
A random UUID generator creates version 4 UUIDs using cryptographically secure random number generation. Unlike version 1 UUIDs (which include timestamp and MAC address), random UUIDs are purely random, making them impossible to predict or reverse-engineer.
When to use random UUID generator:
- Security-sensitive IDs: Session tokens, API keys, authentication tokens (randomness prevents guessing)
- Privacy protection: User IDs that shouldn't reveal creation time or device info
- Distributed systems: Microservices needing unique IDs without central coordination
- Test data: Generating realistic unique identifiers for database testing
- File naming: Unique filenames for uploads without collisions
This random UUID generator uses browser's crypto.getRandomValues() API, providing cryptographically secure randomness suitable for production use. The probability of collision is ~5.3×10^-37, effectively zero for practical purposes.
Bulk UUID Generation - Generate 500 UUIDs Instantly
Developers frequently need to generate UUID in bulk for:
- Database seeding: Populate test databases with realistic primary keys
- API testing: Generate unique request IDs for load testing
- Migration scripts: Create UUIDs for legacy data without unique identifiers
- Mock data: Build test fixtures with unique IDs for CI/CD pipelines
- Batch operations: Generate IDs for bulk insert operations
How to generate UUIDs in bulk:
- Set "Number of UUIDs" to desired quantity (1-500)
- Choose format: uppercase, no-hyphens, or braces as needed
- Click "Generate UUIDs" - instant generation
- Copy to clipboard or download as .txt file
- Paste into SQL scripts, test files, or code
Example: Generating 500 UUIDs takes < 1 second. Perfect for seeding a users table with unique IDs, creating test API requests, or populating a distributed cache with unique keys.
UUID Format Options for Different Use Cases
Different systems expect UUIDs in different formats. This generator supports all common formats:
| Format | Example | Use Case |
|---|---|---|
| Standard (lowercase) | 550e8400-e29b-41d4-a716-446655440000 | Python, Node.js, PostgreSQL, most databases |
| Uppercase | 550E8400-E29B-41D4-A716-446655440000 | SQL Server, Oracle, some Windows apps |
| With braces | {550e8400-e29b-41d4-a716-446655440000} | C#, .NET, Windows Registry, COM objects |
| No hyphens | 550e8400e29b41d4a716446655440000 | Binary storage (BINARY(16)), some APIs, MongoDB |
Select the format matching your target system before generating. For SQL INSERT statements, use standard format. For C# code, add braces. For binary database columns, remove hyphens.
UUID in Different Programming Languages
How to generate UUID programmatically vs using this online tool:
JavaScript / Node.js
crypto.randomUUID() // Built-in, Node 14.17+
Python
import uuid
uuid.uuid4() # Returns UUID object
str(uuid.uuid4()) # Returns string
Java
import java.util.UUID;
UUID.randomUUID().toString();
C# / .NET
using System;
Guid.NewGuid().ToString();
PHP
// PHP 7+
$uuid = sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
mt_rand(0, 0xffff), mt_rand(0, 0xffff),
mt_rand(0, 0xffff),
mt_rand(0, 0x0fff) | 0x4000,
mt_rand(0, 0x3fff) | 0x8000,
mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
);
Ruby
require 'securerandom'
SecureRandom.uuid
When to use online generator vs code: Use programmatic generation for runtime UUID creation in production apps. Use this online generator for test data, migration scripts, manual database inserts, configuration files, and ad-hoc bulk generation needs.
Support
Frequently Asked Questions
20+ frequently asked questions about UUID and GUID generation, covering "what is uuid", "uuid vs guid", formatting, security, and use cases.
20 Frequently Asked Questions - Covering UUID basics, GUID differences, bulk generation, formats, programming languages, and security.
UUID (Universally Unique Identifier) is a 128-bit unique identifier standardized by RFC 4122. UUIDs are used in software development to uniquely identify information without a central authority. A UUID looks like: 550e8400-e29b-41d4-a716-446655440000
GUID (Globally Unique Identifier) is Microsoft's implementation of UUID. GUID and UUID are functionally identical - both are 128-bit unique identifiers. The terms are interchangeable, with GUID being the Microsoft/Windows terminology and UUID being the universal standard term.
UUID and GUID are the same thing. UUID is the standardized term (RFC 4122), while GUID is Microsoft's name for the same concept. Both are 128-bit unique identifiers with the same format and generation algorithms. Use a UUID generator or GUID generator - they produce identical results.
To generate UUID online free: 1) Set the number of UUIDs needed (1-500). 2) Choose format options (uppercase, no-hyphen, braces). 3) Click 'Generate UUIDs'. 4) Copy output or download as TXT. The tool runs 100% in your browser with no server upload required.
This tool generates RFC 4122 compliant UUID version 4 (random) values based on cryptographically secure random bytes using the crypto.getRandomValues API.
Yes, set the batch count and generate up to 500 UUIDs in one click for bulk generation needs.
Yes, you can toggle uppercase letters and braces {UUID} around each UUID for Microsoft GUID format compatibility.
Yes, use no-hyphen mode to output compact UUID strings (32 characters) useful for binary database storage.
Yes, completely free with unlimited UUID/GUID generation. No registration, subscription, or hidden costs.
No, generation runs entirely in your browser and no UUID data is uploaded. All generation happens client-side using JavaScript crypto API.
Yes, this random UUID generator supports bulk generation of up to 500 UUIDs at once. Set the quantity, choose format options, and generate all IDs instantly.
In C#, use Guid.NewGuid() to generate a new GUID: `Guid newGuid = Guid.NewGuid();`. To get string format: `string guidString = newGuid.ToString();`. For bulk generation, use this online GUID generator instead of writing loops.
A UUID is 128 bits (16 bytes) long. In standard string format with hyphens, it's 36 characters: 32 hexadecimal digits + 4 hyphens (8-4-4-4-12 format). Without hyphens (compact format), it's 32 characters.
UUID v1 uses timestamp + MAC address (can expose hardware info). UUID v4 uses random generation (more secure, no hardware info leak). V4 is recommended for most use cases. This tool generates UUID v4 for maximum privacy and security.
Yes, UUIDs work as database primary keys. Benefits: distributed systems friendly, no central ID authority needed, prevent ID guessing. Drawbacks: larger storage (16 bytes vs 4-8 bytes for INT), slightly slower indexing. Use UUID v7 or ULID for better database performance.
In Java, use UUID.randomUUID(): `import java.util.UUID; UUID uuid = UUID.randomUUID(); String uuidString = uuid.toString();`. This generates UUID v4 (random). For bulk needs, use this online UUID generator.
GUID format is: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where x is any hex digit (0-9, a-f), 4 indicates version 4, and y is 8, 9, a, or b. Example: 550e8400-e29b-41d4-a716-446655440000. GUIDs can also be formatted with braces {GUID} or uppercase.
Yes, this UUID generator uses crypto.getRandomValues() which provides cryptographically secure random numbers. UUID v4 generation is secure for session tokens, API keys, and database IDs. The randomness makes UUIDs impossible to guess or predict.
UUID collision probability is astronomically low: ~1 in 2^122 (5.3×10^36). You'd need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of one collision. For practical purposes, UUIDs are guaranteed unique.
Empty GUID (null GUID) is all zeros: 00000000-0000-0000-0000-000000000000. It represents a null/empty value in GUID fields, similar to null in databases. Never use empty GUID as an actual identifier - always generate a new random GUID.
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🔑 UUID & GUID Generator - Complete Overview
This free UUID generator online and GUID generator creates RFC 4122 compliant version 4 identifiers instantly. With 50,000+ developers using daily, it's the most trusted tool for generating random UUIDs and GUIDs in bulk (up to 500 IDs per generation). Unlike other UUID generators, this tool runs 100% in your browser using cryptographically secure random number generation (crypto.getRandomValues API), ensuring your IDs are never sent to any server.
What is UUID vs GUID? UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are identical - both are 128-bit unique identifiers following RFC 4122 standard. UUID is the universal term used by Python, Java, JavaScript, PostgreSQL, while GUID is Microsoft's terminology used in C#, .NET, SQL Server. This generator produces both formats interchangeably. When developers search for "guid generator", "uuid generator", "generate uuid", or "generate guid", they're looking for the same tool.
Key Features: ✅ Bulk UUID generation - Generate up to 500 random UUIDs instantly | ✅ Multiple formats - Standard lowercase, UPPERCASE, with {braces}, no-hyphens (compact 32-char format) | ✅ RFC 4122 v4 compliant - Industry-standard UUID version 4 (random) | ✅ Cryptographically secure - Uses browser crypto API for secure randomness | ✅ 100% private - No server upload, all generation happens locally | ✅ Copy & download - One-click clipboard copy or TXT file download | ✅ Free forever - Unlimited UUID/GUID generation, no limits | ✅ Cross-platform - Works on Windows, Mac, Linux, all browsers | ✅ Mobile-optimized - Fully responsive, works on phone/tablet.
Common Use Cases: Developers use this UUID generator online free tool for: Database seeding - Generate bulk UUIDs for test database primary keys. API development - Create unique request IDs, correlation IDs, transaction IDs for microservices. Test data - Generate realistic unique identifiers for CI/CD pipelines and test fixtures. Session tokens - Create secure, unpredictable session identifiers. File naming - Generate unique filenames preventing upload collisions. Distributed systems - Unique IDs across services without central coordination. Migration scripts - Add UUIDs to legacy data. C# / .NET development - Generate GUIDs matching System.Guid.NewGuid() output. SQL Server - Create UNIQUEIDENTIFIER column values. MongoDB - Generate document _id values.
Why Choose This UUID Generator? Unlike desktop tools (guidgen.exe, Visual Studio "Create GUID") that generate one ID at a time, this online tool excels at bulk UUID generation. Generate 500 UUIDs in under 1 second for database seeding, test data creation, or API load testing. The format options support all common UUID representations: standard format (550e8400-e29b-41d4-a716-446655440000), Microsoft GUID format with braces ({550E8400-E29B-41D4-A716-446655440000}), compact no-hyphens format (550e8400e29b41d4a716446655440000), and more. The tool remembers your format preferences for repeated use.
UUID Security & Uniqueness: This random UUID generator uses UUID version 4, which relies on cryptographically secure random number generation. The probability of UUID collision is ~5.3×10^-37 (practically zero). You could generate 1 billion UUIDs per second for 85 years and still have less than 50% chance of a single collision. This makes UUIDs perfect for distributed systems where nodes generate IDs independently without coordination. The crypto.getRandomValues() API provides security suitable for session tokens, API keys, and authentication identifiers - UUIDs are impossible to guess or predict.
UUID Format Comparison: Standard UUID format (36 characters with hyphens) is supported by all databases: PostgreSQL UUID type, MySQL CHAR(36), MongoDB strings. Compact format (32 characters, no hyphens) is optimal for binary storage: PostgreSQL BINARY(16), SQL Server UNIQUEIDENTIFIER, MySQL BINARY(16). Braced format {GUID} is standard in Windows Registry, COM objects, .NET configuration files. Uppercase format is common in Oracle, SQL Server, and Microsoft documentation. This generator supports all formats with one-click toggling.
Get Started: No registration or setup required. Simply enter the number of UUIDs you need (1-500), select your preferred format options, and click "Generate UUIDs". Copy to clipboard for immediate use, or download as a .txt file for batch processing. Works in all modern browsers: Chrome, Firefox, Safari, Edge. Last updated: May 27, 2026 | Rating: 4.9/5 stars (342 reviews) | Daily users: 50,000+ developers worldwide | Total UUIDs generated: 500M+ since launch.