Every UUID generator I found online defaults to v4. That was correct in 2015. It is not correct anymore.
I built one that defaults to v7. It also does v1, v3, v4, and v5. Batch up to one thousand at once, download as TXT, CSV or JSON, generate SQL-ready INSERT rows or skip the UI and hit the public API from your terminal.
Why v7 beats v4 for database keys
UUID v4 is fully random. Every insert lands at a random spot in your B-tree index. Every insert forces a page split. Every insert amplifies I/O.
For a small table this does not matter. For a table with a hundred million rows, it is a big part of why your database is slow.
UUID v7 embeds a millisecond timestamp in the first forty-eight bits. Inserts land at the end of the index. Same uniqueness guarantees as v4, same distributed generation, but the write pattern of an auto-incrementing integer.
If you are picking a UUID version for a new table today, pick v7.
When to still use v4
- You explicitly do NOT want the ID to reveal when it was created. Public-facing IDs where creation order would leak user activity.
- Your database or ORM does not yet support v7. Rare in 2026, but worth checking.
That is it. Anywhere else, v7 is the better default.
The API
Skip the UI entirely:
curl "https://nimoyburrowes.com/api/tools/uuid?count=100&v=7&text=1"
CORS is open, so it works from browser JavaScript too. The endpoint is stateless and does not log the values it returns.
Try it
