UUID, ULID, and NanoID Generator

Generated in your browser.

Generate up to 1,000 identifiers at once with the browser's cryptographic random number generator, then paste any ID back in to see its version and the time it was made.

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About 2uuid

How Can You Verify That Nothing Leaves This Browser?

You do not have to take our word that your data stays here. Developer tools show every request a page makes, so you can watch this page work and confirm that nothing is sent. The check takes under a minute.

Open your browser developer tools with F12, or Cmd+Option+I on a Mac, and select the Network tab.
Reload the page and let it finish. You will see the page's own files, its web fonts, and one anonymous page-view request. Nothing has been typed yet, so none of them can contain your data.
Click the clear icon in the Network tab so that the log is empty.
Use the tool with your own input.
Look at the Network tab again. It is still empty. For extra proof, turn on offline mode after the page loads and the tool keeps working.

Only two things can add a line to that log, and neither carries your data. Submitting the feedback form sends the vote and comment you typed. Typing characters in a script the page has not displayed yet, such as Cyrillic or Greek, can make the browser fetch the matching font file, and that request names only the font.

The production site also sends a Content-Security-Policy header that tells your browser to refuse connections to anywhere except this site and the anonymous analytics endpoint, so a coding mistake could not quietly send your data elsewhere.

What Is a UUID?

A UUID, or universally unique identifier, is a 128-bit value written as 32 hexadecimal digits in five groups, such as 0190f3c2-7a4e-7b3d-9a1c-3f2e4d5c6b7a. The digit after the second dash is the version, and the first digit of the fourth group encodes the variant. RFC 9562, published in 2024, is the current standard and defines versions 1 through 8.

Any system can create a UUID without asking a central server, and the chance of two random ones colliding is so small that it can be ignored in practice. That is why they are the default primary key in many databases and the standard way to name events, files, and requests.

Should You Use UUID v4 or v7?

Version 4 is 122 random bits. It reveals nothing about when or where it was made, which is ideal for public tokens. Its randomness is also its weakness as a database key: new rows land at random places in the index, which fragments B-tree pages and slows inserts on large tables.

Version 7 starts with a 48-bit Unix timestamp in milliseconds, followed by random bits. New IDs sort after older ones, so inserts append to the end of the index, and you can read the creation time back out. 2uuid also makes v7 monotonic within a millisecond, so a bulk batch sorts in the exact order it was generated. Use v7 for keys and v4 when the creation time should stay private.

How Do ULID and NanoID Compare?

ULID: 128 bits like a UUID, a 48-bit timestamp plus 80 random bits, written as 26 Crockford base32 characters. It sorts by time and avoids look-alike letters such as I, L, O, and U.
NanoID: a short random string, 21 URL-safe characters by default, with about the same collision resistance as UUID v4. You can choose the length and the alphabet. It carries no timestamp.

2uuid uses rejection sampling for NanoID, so every character in a custom alphabet is equally likely.

What Can the Decoder Tell You?

Paste an ID and 2uuid detects its type. For UUID v1 and v6 it reads the 60-bit Gregorian timestamp, the clock sequence, and the node field. For v7 and ULID it reads the millisecond timestamp and shows it in UTC and in your local time. For v4, v3, and v5 it explains why there is no time to read. It also recognizes the nil and max UUIDs and accepts braces and the urn:uuid: prefix.

The vanilla 2uuid this tool replaces truncated timestamps to 32 bits and could not detect v7 at all. Both bugs are fixed and covered by tests.

What Other Tools Are in the Generators Lane?

2gitignore: Pick your languages, frameworks, OS, and editor; get one merged, de-duplicated .gitignore.
2csp: Build a Content-Security-Policy header or meta tag, with nonces, hashes, strict-dynamic, and Report-Only.
2htaccess: Apache rules for HTTPS, www canonical, compression, caching, headers, file blocking, and SPA fallback.
2robots: A robots.txt with your sitemap, private paths, crawl delay, and plain-English notes.

Elsewhere in the toolbox: 2hash, 2base, 2otp, 2xml, and more on the 2toolbox home page. Part of the 2suite.io privacy-first ecosystem.

Frequently Asked Questions

Are these UUIDs truly random?

Yes. They come from crypto.getRandomValues, the browser's cryptographically secure random number generator. Nothing is generated on a server.

Can two UUID v7 values from one batch be out of order?

No. Within one millisecond 2uuid increments a 12-bit counter, so every batch sorts in generation order.

Does a UUID v7 leak information?

It reveals the millisecond it was created. If that matters, for example in a public URL, use v4 instead.

Is NanoID safe to use as a database key?

Its randomness matches UUID v4, so collisions are not a practical concern. It is shorter but does not sort by time.

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