Tools / UUID Generator
UUID Generator
Generate UUID v4 identifiers in bulk, right in your browser. Choose the count, case, and format — nothing is uploaded.
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// About this tool
UUID Generator
This UUID generator creates random version-4 UUIDs using your browser's cryptographic random number generator. Generate a single identifier or up to 100 at once, in lowercase or uppercase, with or without the standard dash separators.
Everything runs locally — nothing is uploaded, and the generator works fully offline. There is no server involved, so there is nothing to log and no rate limit.
UUID v4 is the standard random format, ideal for database keys, test data, file names, and any identifier where you need 122 bits of randomness.
Why a browser generator over a command-line one: crypto.randomUUID() or uuidgen are fine when you're in a shell, but bulk workflows — seed files, fixture data, batch insert scripts — want a copy-paste block of dozens at once with the exact casing and separator format your target system expects. This generates them with the Web Crypto API's CSPRNG (the same quality source your OS uses), entirely client-side. One honest caveat that generator sites gloss over: UUID v4 IDs are collision-resistant but not sequential, so as a primary key in a database with a B-tree index they scatter writes across the index — fine at moderate scale, worth considering ULIDs or UUIDv7 for write-heavy tables.
// When to use it
Seed a database with test data
Generate 50 UUIDs at once and paste them into a seed script or fixture file.
Create unique file or object names
Generate a fresh identifier for a file, S3 object, or entity that needs a collision-resistant name.
Work in uppercase or no-separator formats
Some systems want uppercase UUIDs or 32-char hex with no dashes — the options cover both without manual reformatting.
// Questions
Is my UUID uploaded anywhere?
No. Generation happens entirely in your browser using the Web Crypto API. Nothing is sent to a server.
What UUID version does this generate?
Version 4 (random). Each UUID is built from cryptographically random bytes, so identifiers are collision-resistant for practical purposes.
Can I generate more than 100 at once?
The UI caps the count at 100, but you can hit Regenerate as many times as you like — there is no server-side limit because nothing is uploaded.
Does it work offline?
Yes. The generator uses only browser APIs, so it works with no network connection at all.
Are UUID v4 values really unique?
Unique in practice, not guaranteed in mathematics. Each UUID v4 carries 122 random bits; the probability of a collision among 103 trillion v4 UUIDs is about one in a billion. Databases still enforce primary-key constraints, and that's the right safety net — but for identifiers, you will never see a v4 collision.
What's the difference between UUID v4 and UUID v7?
v4 is purely random. v7 embeds a millisecond timestamp in the high bits, which makes generated IDs roughly sortable and friendlier to database index locality. Use v4 for general identifiers, test data, and anything non-time-ordered; consider v7 when you're generating millions of rows and B-tree write amplification shows up in profiling.
Is generating UUIDs in the browser secure?
The generator uses crypto.getRandomValues, the browser's cryptographically secure random source — the same class of CSPRNG behind TLS key generation. UUIDs generated here are safe as session identifiers, API keys bases, or any other security-sensitive use, and none of them are ever transmitted or logged.
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