ToolSnap
Generator

UUID Generator

Generate cryptographically secure version 4 UUIDs in your browser. Bulk generation, one-click copy — all offline, no data leaves your device.

How to use

Choose how many UUIDs you need (1–100), toggle uppercase if your system requires it, and click Generate. Each UUID appears in its own row with a copy button.

Click Copy all to copy every UUID as a newline-separated list, ready to paste into a file or database seed script.

All generation happens in your browser using the Web Crypto API — no UUIDs are sent to any server.

Use cases

  • Primary keys for database rows when you need IDs before saving to the server
  • Seeding test data — generate 50 UUIDs and paste them into a SQL or JSON fixture file
  • Correlation IDs for distributed system requests and log tracing
  • Unique file names to avoid naming collisions in object storage (S3, R2)
  • Session or token identifiers in authentication flows

Limitations

This tool generates UUID v4 only. If you need v1 (time-based), v5 (name-based SHA-1), or v7 (monotonic sortable), a dedicated library like the npm uuid package is the right choice.

Maximum batch size is 100 UUIDs at once. For bulk generation of thousands of IDs, use a script with crypto.randomUUID() directly.

Frequently asked questions

What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit label used to identify information in computer systems. It looks like xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx and is designed so that generating one will practically never produce a duplicate.
What is the difference between UUID v1 and UUID v4?
UUID v1 is based on the current timestamp and the MAC address of the machine, which can expose hardware info. UUID v4 is fully random and is the safest and most widely used version for application development.
Are UUIDs truly unique?
Practically, yes. The probability of a collision when generating 2.7 × 10¹⁸ UUID v4s is about 50% — that is 2.7 quintillion. In normal usage, collisions are impossible to encounter.
Are these UUIDs cryptographically secure?
Yes. This tool uses the browser's Web Crypto API (crypto.randomUUID) to generate version 4 UUIDs, which uses a cryptographically secure random number generator.
What is a UUID used for?
UUIDs are used as primary keys in databases, to identify objects in distributed systems, as file or session identifiers, in API request tracking, and anywhere you need a guaranteed-unique value without a central counter.

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