# UUID generator

> Generate random UUID v4 or time-ordered UUID v7 IDs, or ULIDs, up to 1,000 at once. Copy or download as CSV. Uses the browser's secure random source.

URL: https://tools.cuelark.com/uuid-generator
Publisher: Cuelark Team (https://cuelark.com)
Updated: 2026-11-10
Price: free, no sign-up
Privacy: runs in the browser; files are not uploaded

Generate UUIDs in bulk: random version 4, time-ordered version 7 (sorts by creation time, good for database keys) or ULIDs, from your browser's cryptographic random number generator.

## How to use it

1. Choose v4, v7 or ULID and how many (up to 1,000).
2. Press Generate for a fresh batch.
3. Copy them, or download a CSV.

## Details

- **v4:** 122 random bits (RFC 9562)
- **v7:** 48-bit Unix millisecond timestamp + random bits; sorts by time
- **ULID:** 26 Crockford Base32 characters, time-sortable
- **Source:** crypto.getRandomValues / crypto.randomUUID

## Questions

### Should I use UUID v4 or v7?

v7 for database primary keys: it sorts by creation time, so inserts stay close together in indexes. v4 when you don't want the creation time visible in the ID.

### Can two UUIDs collide?

In practice, no. With 122 random bits you'd need to generate about a billion v4 UUIDs a second for decades before a collision became likely.

### Are these UUIDs safe to use as secrets?

They're unpredictable, but UUIDs are designed as identifiers, not tokens. For session tokens or API keys use a dedicated random token of 128 bits or more.

### What is a ULID?

A 128-bit ID written as 26 characters that sorts by time, like 01HF…. It's shorter than a UUID string and safe in URLs.

### Is my input sent anywhere?

No. It is processed by code running in this tab. Nothing is uploaded, logged or saved; tokens, hashes and text are never put in the page address.

### Can an AI agent use this?

Yes. The same function is a tool on our free MCP server at tools.cuelark.com/mcp, so ChatGPT, Claude or Cursor get exactly the answer this page shows. 'Copy MCP call' gives you the arguments.

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