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Free UUID, ULID & NanoID Generator

Generate UUID, ULID & NanoID|
4.9 (1,201)

A free, private unique identifier generator that runs entirely in your browser with zero dependencies. It produces three of the most widely used ID formats: RFC 4122 version 4 UUIDs, lexicographically sortable ULIDs, and compact URL-safe NanoIDs. Every value is generated from cryptographically secure randomness using the native Web Crypto API (crypto.randomUUID and crypto.getRandomValues), the same CSPRNG browsers use for keys and tokens, so the IDs are suitable for production database primary keys, distributed systems, API request identifiers, and idempotency keys. Generate one ID or bulk-generate thousands at once, toggle UUID casing and hyphenation, choose a custom NanoID length, and rely on monotonic ULID generation that guarantees strictly increasing values even within the same millisecond. Copy any single ID, copy the whole batch, or download the results as a .txt file. No signup, no API keys, no network requests: nothing is uploaded, logged, or stored on a server. The generation happens locally on your device and works fully offline once the page has loaded.

Generate UUID, ULID and NanoID securely in your browser

This tool generates three of the most common unique identifier formats without sending a single byte to a server. UUID v4 gives you the universal, 128-bit random standard defined in RFC 4122, perfect when you need a collision-resistant key that any system understands. ULID gives you a 128-bit identifier that encodes its creation time, so a list of ULIDs sorts by when it was made and indexes efficiently in a database. NanoID gives you a compact, URL-safe string that is shorter than a UUID while staying just as hard to guess, which is ideal for share links and public IDs.

Because everything is hand-coded in plain JavaScript with zero third-party dependencies, there is nothing to install and nothing to trust beyond your own browser. Open the page, pick a format, set a count, and generate one ID or thousands instantly. Once the page has loaded it keeps working with no network connection at all, so you can generate IDs offline, on locked-down machines, or inside an air-gapped environment.

Cryptographically secure by default with the Web Crypto API

Every identifier draws its randomness from the native Web Crypto API, the browser cryptographically secure pseudo-random number generator. UUID v4 is produced with crypto.randomUUID, and ULID and NanoID pull their random bits from crypto.getRandomValues. This is the same secure source browsers use to create cryptographic keys and session tokens, which means the IDs are unpredictable and safe to use as real production identifiers, not just throwaway placeholders. The tool deliberately never falls back to Math.random, which is not safe for anything that needs to be unguessable.

ULIDs are assembled exactly as the specification describes: a 48-bit millisecond timestamp from your device clock, followed by 80 bits of secure randomness, encoded in Crockford base32 (an alphabet that omits the ambiguous letters I, L, O, and U). When you generate several ULIDs in the same millisecond, the generator runs in monotonic mode and increments the random portion so each value is strictly greater than the last, keeping a fresh batch in stable, increasing order. NanoIDs use the canonical 64-character URL-safe alphabet (A-Za-z0-9_-) and default to 21 characters, the length that balances brevity against an extremely low collision probability, with the length fully adjustable.

Private, offline, and built for real workflows

Many online ID generators quietly call a backend, log your requests, or wrap a paywall around bulk generation. This one does none of that: the logic runs locally, no request is ever made, and no IDs are stored or transmitted. You can verify it at any time by opening the Network tab in your browser DevTools and watching that generating IDs produces no outbound traffic. That makes it safe to generate identifiers for sensitive systems without worrying about them leaking.

The tool is designed for how developers actually use IDs. Bulk-generate a batch to seed test fixtures, mock data, or load tests. Toggle UUID uppercase and hyphens to match whatever your database or filename convention expects. Choose ULIDs when you want keys that sort by time, or short NanoIDs for slugs, invite codes, and public links. When you are done, copy a single value, copy the whole batch, or download everything as a plain .txt file with one ID per line, ready to paste straight into a script, migration, or spreadsheet.

How It Works

1

Pick a format tab: UUID v4, ULID, or NanoID, then set how many IDs you want to generate at once.

2

Adjust format options like UUID uppercase or hyphen toggles and NanoID length, then click Generate.

3

Copy a single ID, copy the entire batch to your clipboard, or download all results as a .txt file.

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Key Features

Three formats in one tool: RFC 4122 version 4 UUID, time-sortable ULID, and URL-safe NanoID
Cryptographically secure randomness from the native Web Crypto API (crypto.randomUUID and crypto.getRandomValues), the same CSPRNG used for cryptographic keys
UUID v4 generated with the browser native crypto.randomUUID with uppercase and hyphen toggles for any storage convention
ULID built from a 48-bit Date.now() timestamp plus 80 bits of randomness, encoded in Crockford base32 (no I, L, O, or U) so it stays sortable and human-safe
Monotonic ULID generation that guarantees strictly increasing values within the same millisecond, matching the ULID specification monotonic factory
NanoID over the standard 64-character URL-safe alphabet (A-Za-z0-9_-) with an adjustable length, defaulting to the canonical 21 characters
Bulk generation of one to thousands of IDs at once with copy-all and download-as-text export
Runs 100% client-side with zero third-party dependencies: nothing is uploaded, logged, or stored on a server

Privacy & Trust

All IDs are generated locally in your browser: no request ever reaches a server, so nothing is uploaded, logged, or stored remotely
Randomness comes from the Web Crypto API CSPRNG (crypto.getRandomValues / crypto.randomUUID), not the insecure Math.random, so the output is unpredictable and safe for production identifiers
No account, signup, API key, or tracking is required to generate any number of IDs
Verify privacy yourself by opening the Network tab in your browser DevTools while generating: you will see no outbound requests carrying your IDs

Use Cases

1Create primary keys for database rows, documents, or distributed records without coordinating with a central server
2Generate ULIDs as time-sortable keys so records naturally order by creation time and index efficiently
3Produce short, URL-safe NanoIDs for share links, slugs, invite codes, and public-facing resource IDs
4Generate idempotency keys, correlation IDs, and request IDs for API calls and event-driven systems
5Seed test fixtures, mock data, and load tests by bulk-generating thousands of unique identifiers at once
6Stub config values, feature flags, or message IDs during local development without installing a CLI or library

Limitations

  • These are random or time-based IDs, not sequential auto-increment integers, so they do not produce a compact 1, 2, 3 numbering scheme
  • ULID timestamps come from your device clock, so a badly skewed system clock can affect their sort order across machines
  • Cryptographic strength depends on your browser implementing a secure Web Crypto API, which all modern browsers do; very old browsers may fall back or fail
  • Generated IDs exist only in the current page session: they are not saved or synced anywhere after you leave or reload the page

Q&A SESSION

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Frequently Asked Questions

Is this UUID, ULID and NanoID generator free?

Yes, it is completely free with no limits. You can generate a single ID or bulk-generate thousands at a time, in any of the three formats, without paying, signing up, or installing anything. The tool is hand-coded with zero third-party dependencies and runs entirely in your browser, so there is no cost and no usage cap.

Are the generated IDs cryptographically secure?

Yes. Every value is built from the native Web Crypto API, the browser cryptographically secure pseudo-random number generator. UUID v4 uses crypto.randomUUID, while ULID and NanoID draw their random bits from crypto.getRandomValues. This is the same source browsers use for cryptographic keys and tokens, so the output is unpredictable and safe to use as production identifiers. The tool never uses the insecure Math.random.

Are my generated IDs sent to a server?

No. Generation happens entirely on your device inside the browser using the Web Crypto API. No IDs, settings, or metadata are uploaded, logged, or stored remotely, and there is no account or API key involved. You can confirm this by opening the Network tab in your browser DevTools while generating: you will see no outbound requests carrying your IDs.

What is the difference between UUID, ULID, and NanoID?

A UUID v4 is a 128-bit random identifier in the standard 36-character hyphenated form (RFC 4122), ideal as a universal, collision-resistant key. A ULID is also 128 bits but encodes a 48-bit timestamp followed by 80 random bits in Crockford base32, so ULIDs are lexicographically sortable by creation time and index well in databases. A NanoID is a compact, URL-safe string (default 21 characters from A-Za-z0-9_-) that is shorter than a UUID while staying collision-resistant, which makes it great for links and public IDs. Pick UUID for maximum compatibility, ULID when time ordering matters, and NanoID when you want short, URL-friendly IDs.

Do I need to install anything or use it online only?

There is nothing to install: it is a single web page that runs in any modern browser. The generation logic is plain JavaScript with no libraries, so once the page has loaded it works fully offline. You can generate as many IDs as you like with no network connection, which is useful on locked-down or air-gapped machines.

Are ULIDs guaranteed to sort correctly within the same millisecond?

Yes. This generator uses monotonic ULID generation: when multiple ULIDs are created in the same millisecond, the random component is incremented rather than re-randomized, so each new ULID is strictly greater than the previous one. That matches the ULID specification monotonic factory and keeps a freshly generated batch in stable, strictly increasing order.

Can I generate many IDs at once and export them?

Yes. Set the count to any number and click Generate to produce a full batch instantly. You can copy a single ID with one click, copy the entire batch to your clipboard, or download all of them as a plain .txt file (one ID per line). This makes it easy to seed test data, populate fixtures, or paste a list straight into a script or spreadsheet.