UUID 產生器

使用方法

Choose a version and a count (1–100), then press Generate. v4 UUIDs are built from cryptographically secure random bytes. v7 UUIDs embed a millisecond timestamp at the front, so they sort in creation order and work well as database keys. You can also switch to uppercase or drop the hyphens. The validator at the bottom checks an existing UUID's format and reports its version and variant.

注意事項

Randomness comes from the browser's crypto.getRandomValues, and generated UUIDs are never sent to a server. Output without hyphens is not the standard UUID text format, and the page says so. Validation only checks the format and the version/variant bits — it cannot prove who issued a UUID.

常見問題

Should I use v4 or v7?

v4 is fine for general use. Prefer v7 when you want time-ordered IDs or better database index behavior — but note that v7 reveals roughly when it was created.

Can generated UUIDs collide?

v4 carries 122 random bits, so collisions are not a practical concern.