Are generated UUIDs sent to a server?

No. crypto.getRandomValues uses the browser's secure RNG locally — neither the process nor the output leaves your device.

Should I use v4 or v7?

Use v7 for database primary keys or any time-ordered ID: the timestamp prefix keeps B-tree indexes from fragmenting. Use v4 for fully unpredictable random IDs (tokens, one-off identifiers).

Will UUIDs ever collide?

v4 carries 122 bits of randomness; collision probability is negligible (~10^-18 after a billion IDs). v7 mixes a millisecond timestamp with 74 bits of randomness, which is more than enough even within the same millisecond.

Is this the same as a GUID?

Effectively yes. GUID is Microsoft's term, UUID is the RFC 4122 / 9562 standard term — formats are compatible. Use the braces format to match Windows-style GUID strings.

Back to Developer

UUID generator — v4 / v7 batch generation

Generate UUID v4 (random) or UUID v7 (timestamp-prefixed) in batches of 1–100. Backed by crypto.getRandomValues and runs entirely in your browser.

developergenerate

Version

Fully random — no ordering. Not ideal as a database PK because it fragments B-trees.

Count:Format:Casing:

Generated UUIDs

Press Generate to produce UUIDs here.

UUIDs are generated inside your browser only

How to use

Pick version (v4 / v7), count (1–100), format (hyphenated / compact / braces), and casing, then press Generate. Each row has a Copy button; Copy all dumps every UUID separated by newlines. crypto.getRandomValues provides the cryptographically secure random bits, so the output is RFC-compliant and suitable for production use.

FAQ

Are generated UUIDs sent to a server?: No. crypto.getRandomValues uses the browser's secure RNG locally — neither the process nor the output leaves your device.
Should I use v4 or v7?: Use v7 for database primary keys or any time-ordered ID: the timestamp prefix keeps B-tree indexes from fragmenting. Use v4 for fully unpredictable random IDs (tokens, one-off identifiers).
Will UUIDs ever collide?: v4 carries 122 bits of randomness; collision probability is negligible (~10^-18 after a billion IDs). v7 mixes a millisecond timestamp with 74 bits of randomness, which is more than enough even within the same millisecond.
Is this the same as a GUID?: Effectively yes. GUID is Microsoft's term, UUID is the RFC 4122 / 9562 standard term — formats are compatible. Use the braces format to match Windows-style GUID strings.

Related tools

UUID parser — version, variant, timestamp

Paste a UUID and inspect its version (v1–v8 / Nil / Max), variant (RFC 9562 / Microsoft / legacy NCS), canonical / compact / braced / URN forms, integer (BigInt), and raw bytes — all at once. UUID v1 and v6 expose the embedded timestamp + node MAC, and UUID v7 reveals the Unix epoch ms used as the prefix. Braces, whitespace, the urn:uuid: prefix, and mixed case are normalized automatically. Nothing leaves the browser.

developerdecode

Password generator — strength, char sets, length

Generate strong random passwords in batches of 1–25. Pick length, character sets, and toggle look-alike exclusion. Backed by crypto.getRandomValues and runs entirely in your browser.

developersecuritygenerate

Hash generator — SHA-1 / 256 / 384 / 512

Generate SHA-1, SHA-256, SHA-384, and SHA-512 digests from text in parallel. Powered by the Web Crypto API and runs entirely in your browser.

developerhashgenerate

Dice roller — 2d6+3 / 4d6kh3 notation (Web Crypto, no server)

Roll TTRPG / board-game dice using familiar notation: 2d6+3, 1d20-2, 4d6kh3 (keep highest 3), 3d6+1d4-1, and more. Randomness uses the Web Crypto API (crypto.getRandomValues with rejection sampling) for an exactly uniform distribution. Comes with one-click presets (d4 / d6 / d8 / d10 / d12 / d20 / d100 / 3d6 / 4d6kh3, …) and an in-browser history of the last 20 rolls. Nothing is uploaded.

developergenerate