UUID v4 Generator
Generate between 1 and 10 UUID v4 values at once using the browser's crypto API. Each UUID is RFC 4122-compliant. Copy individually or grab them all in one click.
Used 7,300 times
Latest Developer Tools articles
HEX ↔ RGB ↔ HSL Color Converter
Convert colors between HEX, RGB, and HSL, build palettes, and ensure accessible contrast. Includes CSS snippets and WCAG guidance.
Compare Text Online – Diff Checker Tool Guide
Learn how to use an online diff checker to compare two text blocks, spot code changes, and catch config mismatches — with line-by-line highlighting and practical examples.
.env File Editor – Keep Environment Variables Consistent
Standardize .env files across dev, staging, and production. Learn how to sort keys, deduplicate secrets, and avoid missing variables.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier standardized in RFC 4122. Version 4 UUIDs are randomly generated — the probability of a collision is astronomically low, making them safe to use as primary keys, idempotency tokens, file names, and correlation IDs without a central registry. Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx.
How to Use
- Set the count (1–10) using the input field.
- Click Generate to produce new UUIDs.
- Click the copy icon next to any UUID to copy it individually.
- Click Copy All to copy all generated UUIDs as a newline-separated list.
Common Use Cases
- Database primary keys — Avoids sequential ID enumeration and works across distributed systems.
- Idempotency tokens — Pass a UUID as a request ID to safely retry API calls.
- Test fixtures — Seed test data with predictable-format but unique identifiers.
- Temporary file names — Name uploads or temp files without collision risk.
FAQs
Are these UUIDs truly random?
Yes. They use crypto.randomUUID() (or crypto.getRandomValues() as a fallback), both backed by the OS CSPRNG — the same source used for TLS key generation.
What is the difference between UUID v4 and v7?
UUID v4 is purely random. UUID v7 (newer) embeds a millisecond timestamp in the high bits, making it sortable — useful for time-ordered database indexes. This tool generates v4.
Is it safe to use UUIDs as public-facing IDs?
Generally yes — they do not leak sequence or count information. However, they are not secrets; do not use a UUID alone to authorize access to a resource.