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About This Tool
UUID (Universally Unique Identifier) or GUID is a 128-bit unique identifier used to mark data, objects, or entities in computer systems. UUIDs are commonly used in databases, APIs, distributed systems, and modern applications that require identifiers without collision. UUIDs ensure no duplicate IDs, no need for auto-increment from database, can be created on client-side (browser/app) without server, and are safe for distributed systems.
How to Use
Select UUID version (default v4), specify the number of UUIDs to generate, configure output format according to your needs (hyphens, uppercase, braces, etc.), and UUIDs will appear automatically in the output. Click copy button to copy all results. All processing is done entirely in the browser, without server—safe and fast.
Common Use Cases
Database IDs
Use UUID as primary key in PostgreSQL, MongoDB, or MySQL for distributed systems without auto-increment conflicts.
API Resource IDs
RESTful API endpoints like /users/{uuid} provide unpredictable IDs for security.
Session & Token IDs
Generate unique session identifiers for user authentication without collision risk.
File & Upload IDs
Assign unique IDs to uploaded files to prevent naming conflicts.
Event Tracking
Distributed logging systems use UUIDs to track events across microservices.
Temporary IDs
Frontend applications can generate UUIDs before syncing with backend.
Limitations & Important Notes
UUIDs are 128-bit (36 characters with hyphens) which is larger than auto-increment integers—this impacts storage space and index size in databases. UUID v4 (random) has no inherent ordering which may affect database performance for range queries—consider UUID v7 for time-sortable IDs. UUID v1 includes MAC address which may expose hardware information—avoid if privacy is critical. Browser-generated UUIDs use crypto.randomUUID() which is secure but requires modern browsers (Chrome 92+, Firefox 95+, Safari 15.4+). For high-volume generation (millions per second), server-side generation with optimized libraries may perform better.
Created by Sofyan Setiawan – Full-Stack Developer
Software engineer with 8+ years of experience building web applications, developer tools, and API integrations. Creator of CodingTool.dev, helping developers with everyday coding tasks.