"category": "dev-utility",
UUID Generator (v4 & v7)
"tldr": Generate up to 1,000 UUIDs at once - random v4 or time-sortable v7 - entirely in your browser with crypto-grade randomness.
Generate universally unique identifiers in bulk: classic random v4 or the newer time-sortable v7, up to 1,000 per click, using the browser's cryptographic random source. Copy the list or download it as a file for seeding databases and fixtures.
The v4/v7 choice matters more than it looks: v4 is pure randomness, while v7 embeds a millisecond timestamp in the leading bits - so v7 IDs sort by creation time, which keeps database B-tree indexes compact instead of fragmenting them with random inserts. New systems with UUID primary keys should almost always pick v7.
How to generate UUIDs
- 1Pick the version: v4 (random) or v7 (time-sortable).
- 2Set how many you need - up to 1,000 per batch.
- 3Click Generate; toggle Uppercase if your convention needs it.
- 4Copy the list or download uuids.txt.
Convert Options to UUIDs in code
crypto.randomUUID(); // v4, built into browsers and Node 19+
// v7: npm install uuid
import { v7 as uuidv7 } from "uuid";
uuidv7();import uuid
uuid.uuid4() # random
# Python 3.14+: uuid.uuid7() - stdlib time-sortableFrequently asked questions
UUID v4 vs v7 - which should I use?
v7 for database keys and anything ordered by creation: its timestamp prefix means sequential inserts and sortable IDs. v4 when order must not leak timing information (public tokens where creation time is sensitive) or for compatibility with systems that validate version bits. Both are 128-bit and equally unique in practice.
Can generated UUIDs collide?
Not in any practical sense: v4 has 122 random bits - generating a billion per second for a century leaves collision odds around one in a billion. Collisions in the wild come from broken generators (seeded PRNGs, copy-paste), not from the math. This tool uses crypto.getRandomValues, the browser CSPRNG.
Is it safe to use UUIDs as public identifiers?
Yes for unguessability (v4 especially), with two caveats: v7 leaks creation time by design, and a UUID is an identifier, not an access control - never let "the URL is unguessable" substitute for authorization checks.
Last updated:
You might also need
Free and in-browser, like everything on JSON Console. Browse all tools →