A UUID generator creates universally unique identifiers you can use as database keys, API tokens, or distributed system IDs. Paste nothing, set your count, and instantly generate cryptographically random UUID v4 strings. Whether you are building an app, designing a database schema, or creating test data, this free online UUID generator gives you instant, secure results. No signup required. Try it now for instant results.
Try the Free Online UUID Generator
How It Works
Step 1: Set the number of UUIDs
Choose how many UUIDs you need, from 1 to 100. If you only need a single identifier for a database key, leave the default at 1. For bulk operations like seeding a test database or generating session tokens for multiple users, increase the count to your desired number.
Step 2: Click Generate
The tool uses the browser's built-in Web Crypto API to generate cryptographically random bytes. These bytes are formatted into the standard UUID v4 structure: 32 hexadecimal digits arranged in five groups separated by hyphens (8-4-4-4-12), with version and variant bits set correctly.
Step 3: Copy and use
Each UUID appears on its own line. Click the Copy button to grab all generated UUIDs at once, then paste them directly into your database, code, or configuration file. Each click of Generate produces a completely new set of unique identifiers.
Real-World Examples
Database Primary Key (Developer): You are designing a distributed PostgreSQL database where multiple application servers insert records simultaneously. Using auto-incrementing integers causes ID conflicts during replication. You switch to UUID v4 as the primary key. Each server generates independent, collision-free identifiers without coordination. The merge completes without a single duplicate key error.
API Resource Identifier (Architect): Your REST API exposes user profiles at /api/users/{id}. Sequential integer IDs let attackers guess the next resource (enumeration attack). You replace them with UUIDs like a1b2c3d4-e5f6-7890-abcd-ef1234567890. Attackers cannot guess the next ID, and your API becomes significantly more secure.
Test Data Seeding (QA Engineer): You need 50 unique order IDs for a load test. Instead of writing a script, you open the UUID generator, set the count to 50, click Generate, and copy the list into your test fixture file. The entire process takes under ten seconds.
Features
- Generates UUID v4 identifiers using the cryptographically secure Web Crypto API
- Supports batch generation of 1 to 100 UUIDs per operation
- 100% private — all generation happens locally in your browser
- Standard 8-4-4-4-12 format compatible with all major databases and frameworks
- One-click copy to clipboard for instant use in your project
- Free forever with no signup, no limits, and no data collection
Use Cases
Developers & Engineers
Generate collision-free primary keys for distributed databases, unique session tokens, and API resource identifiers.
Database Administrators
Seed test databases with unique IDs, migrate data between systems without key conflicts, and design schemas that scale across replicas.
QA & Testers
Create bulk unique identifiers for load testing, regression fixtures, and automated test scripts.
Tips & Best Practices
- Use UUIDs for distributed uniqueness: When multiple servers, databases, or microservices create records independently, auto-incrementing integers collide. UUID v4 removes the need for coordination because every generated value is effectively unique worldwide.
- Store as fixed-size types: In PostgreSQL use the native uuid type or BINARY(16) to keep storage compact. Text columns (CHAR(36)) waste space and index slower. The generated format works with any of these storage strategies.
- Protect against enumeration attacks: Sequential IDs let attackers guess the next resource (e.g., /api/users/1234). Replacing them with random UUIDs makes resource IDs unguessable, improving security for public APIs.
- Generate in bulk for test data: Set the count to 50 or 100 to seed test databases and load-test fixtures in seconds, instead of writing a script or pasting identifiers one at a time.
- Pair with the Hash Generator: For short, URL-safe tokens or cache keys, combine this tool with the Hash Generator to derive compact hashes from your identifiers.
Frequently Asked Questions
Q: What is a UUID?
A: A UUID (Universally Unique Identifier) is a 128-bit identifier represented as 32 hexadecimal digits in five groups separated by hyphens (8-4-4-4-12). UUID v4 uses random numbers and provides approximately 5.3 x 10^36 possible values, making collisions virtually impossible.
Q: What is UUID v4?
A: UUID v4 is a version of the UUID standard that uses random or pseudo-random numbers to generate identifiers. It is the most commonly used version because it does not require coordination between systems and provides sufficient randomness for most applications.
Q: Are these UUIDs cryptographically secure?
A: Yes. Our UUID generator uses the browser's built-in crypto.getRandomValues() API, which provides cryptographically strong random numbers suitable for security-sensitive applications like session tokens and API keys.
Q: Can I generate multiple UUIDs at once?
A: Yes. You can generate between 1 and 100 UUIDs in a single operation. Simply set the desired count and click Generate. Each UUID is unique and independent.
Q: Is the tool secure?
A: Yes. All UUID generation happens locally in your browser using the Web Crypto API. No data is sent to any server, and no identifiers are stored anywhere.
Q: Can I use these UUIDs in my database?
A: Absolutely. UUID v4 is widely supported as a primary key in databases like PostgreSQL, MySQL, MongoDB, and many others. It prevents ID conflicts when merging databases or replicating across servers.