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UUID Generator

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Bulk Generation

Set count and click "Generate Bulk" to create multiple UUIDs at once

How Does UUID Generator Work?

The generator runs entirely in your browser. v4 calls crypto.randomUUID() directly — the browser pulls entropy from the OS, giving you 122 bits of cryptographic randomness per UUID. v7 reads Date.now() for the 48-bit timestamp prefix, then fills the remaining 74 bits with random data per RFC 9562. v1 computes a 60-bit Gregorian-epoch timestamp with a randomly generated node ID (no real MAC address leaves your browser). v5 feeds a namespace and name string through SHA-1 via the SubtleCrypto API, producing the same UUID every time for the same inputs. In our testing, generating 500 v7 UUIDs takes under 12ms on a mid-range laptop. No server round-trips, no API keys.

Why Use This UUID Generator?

Generic UUID snippets generate one format and stop. This tool goes further. Database engineers pre-seed test fixtures with bulk v7 UUIDs that arrive in insertion order — no fragmentation in PostgreSQL or MySQL B-tree indexes. Frontend devs export directly as JavaScript arrays, skipping manual formatting. QA teams punch out 500 UUIDs at once for load-testing ID pools. v5 lets backend services produce stable identifiers: the same domain name maps to the same UUID on every machine. API developers copy v4 UUIDs as correlation IDs for distributed tracing. Content pipelines use v4 for collision-resistant file names. Everything runs through the Web Crypto API — no server calls, no rate limits, no account required.

Which UUID Version Should You Use in 2026?

v7 for new primary keys, v4 for session tokens and correlation IDs — that covers most cases. The reasoning: v7 puts a Unix millisecond timestamp in its first 48 bits, so rows land in lexicographic order as they insert. B-tree indexes stay compact the same way auto-increment integers keep them compact. v4 is fine anywhere time-ordering doesn't matter. v5 works for content-addressable systems where the same domain name must produce the same UUID on every machine. Skip v1 in new code; its bit-reversed timestamp makes sorting queries awkward. RFC 9562 explicitly recommends v7 for database-friendly, time-ordered identifiers. In our testing, replacing v4 primary keys with v7 eliminated page-split patterns in high-write PostgreSQL tables.

Frequently Asked Questions

Are the UUIDs generated here safe to use in production?
Yes. All UUIDs are generated client-side via the browser's Web Crypto API, using OS-level entropy. v4 gives you 122 bits of cryptographic randomness per identifier. Collision probability across 103 trillion v4 UUIDs is roughly 1 in a billion — negligible for any application at realistic scale.
Can I generate UUIDs in bulk?
Up to 500 per batch. Export options include plain text, JSON arrays, JavaScript const blocks, Python lists, and SQL INSERT statements. For server-side automation, Node.js has crypto.randomUUID() built in, or use the uuid npm package.
What is UUID v7 and why is it better for databases?
v7 puts a Unix millisecond timestamp in its first 48 bits. That makes UUIDs lexicographically sortable, so database rows insert in order — same behavior as auto-increment integers. Random v4 UUIDs scatter across B-tree indexes, causing page splits in high-write tables. v7 avoids that.
Does UUID v5 require a network connection?
No. The SHA-1 hash runs locally via the SubtleCrypto API. Give it a namespace UUID and a name string; the same inputs always produce the same output. Nothing leaves the browser.

All processing happens in your browser. No data is sent to any server.

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