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UUID Generator

Generate UUID v4 (random) or UUID v7 (time-ordered) in bulk. Crypto-secure, in your browser, no signup.

  • Runs in browser
  • No signup
  • No tracking
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How to use UUID Generator

  1. Pick a version: v4 (random) or v7 (time-ordered).

  2. Choose how many UUIDs to generate.

  3. Click Generate.

  4. Copy a single ID, or copy all as newline-separated.

When to use it

  • Database primary keys.

  • Idempotency keys for retried API requests.

  • Test fixture IDs that don't collide across runs.

  • Tracking IDs for distributed systems.

What it fixes

  • Random v4 IDs scattering hot pages in B-tree indexes.

  • Auto-increment IDs leaking row counts to clients.

  • Manual UUID generation in a notepad with broken regex.

About UUID Generator

UUID v4 is the workhorse — fully random 128-bit IDs with negligible collision probability. UUID v7 is newer (RFC 9562) and embeds a Unix-millisecond timestamp at the front, so sorting by ID also sorts by creation time.

v7 is preferable when you'll insert many IDs into a B-tree index (Postgres primary keys, Elasticsearch _id) — sequential prefixes mean tighter pages and faster writes.

References: RFC 9562 — UUID (v1–v8) · MDN — crypto.randomUUID

Frequently asked

  • What's the difference between v4 and v7?

    v4 is fully random — great for non-sequential IDs. v7 prefixes a millisecond timestamp, so IDs sort chronologically and play nicer with database B-tree indexes.

  • Where do these IDs come from?

    v4 uses crypto.randomUUID() (cryptographically random). v7 builds the timestamp prefix and fills the rest with crypto.getRandomValues.

  • Is generation private?

    Yes. UUIDs are generated locally in your browser using the Web Crypto API. Nothing is sent to a server.

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