UUID Generator
Generate cryptographically random version 4 UUIDs (Universally Unique Identifiers) in your browser. Using crypto.randomUUID() for true randomness, create any quantity you need — from a single ID to 500 at once. Multiple output formats match different style guides and system requirements: standard, no-dashes, uppercase, and braces-wrapped.
What does this tool do?
The UUID Generator produces version 4 UUIDs, which are completely random (not derived from MAC addresses or timestamps like v1). You can generate from 1 to 500 UUIDs in a single operation. Four formatting options accommodate various use cases: standard (lowercase with dashes, e.g., 550e8400-e29b-41d4-a716-446655440000), no-dashes (compact format for systems that don't allow hyphens), uppercase (for case-sensitive or uppercase-only environments), and braces-wrapped (Microsoft-style with curly braces for registry editing and certain Windows APIs).
How it works
The tool uses the Web Crypto API's crypto.randomUUID() method or crypto.getRandomValues() as a fallback. Version 4 UUIDs follow the standard 8-4-4-4-12 hexadecimal format where specific bits indicate the version (0100 for v4) and variant. The 122 random bits provide approximately 5.3×10^36 possible values, making collisions statistically impossible for any practical generation volume. Formatting transforms the 128-bit value: standard adds dashes at specific positions, no-dashes removes them, uppercase converts hex to A-F, braces wraps with { and }.
Features
- v4 UUIDs from Web Crypto (truly random)
- Generate 1 to 500 UUIDs at once
- Format options: standard, no-dashes, UPPERCASE, {braces}
- Copy individual UUIDs or entire list
- No collision risk in practical use
- No server — 100% client-side generation
- Regenerate for fresh batches
How to use
- 1
Select quantity
Choose how many UUIDs you need: 1 for a single ID, or up to 500 for bulk operations like database seeding.
- 2
Choose format
Standard is what most languages and databases expect. No-dashes for compact storage. Uppercase if your system requires it. Braces for Microsoft-specific contexts.
- 3
Generate
Click Generate. The UUIDs appear in the output area. Each is a unique, cryptographically random v4 identifier.
- 4
Copy what you need
Click individual copy buttons for single UUIDs, or Copy All to grab the entire list for batch operations.
Common use cases
Database primary keys
Generate UUIDs for database records, especially in distributed systems where auto-increment integers cause conflicts.
API and session identifiers
Create request IDs for API logging, session identifiers for web applications, and correlation IDs for distributed tracing.
File and resource naming
Generate unique filenames for user uploads, temporary files, or cache keys that won't conflict.
Testing and development
Create test data with realistic IDs for unit tests, integration tests, and development database seeding.
Tips & best practices
- Standard format (lowercase with dashes) is accepted everywhere — use it unless you have a specific requirement
- v4 UUIDs have 122 random bits — the collision probability is mathematically negligible even with billions of IDs
- Store UUIDs as BINARY(16) in MySQL or uuid in PostgreSQL for efficient storage; the string representation is 36 bytes vs 16 binary
- Use no-dashes format when passing in URLs to avoid the dash being misinterpreted as a minus sign in certain contexts