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CUID Generator

Generate collision-resistant CUIDs in bulk, in the standard or a shorter slug form.

How many to generate, from 1 to 1,000. Everything runs in your browser. Nothing is uploaded.

Format

The full 25-character form, carrying a timestamp, counter, fingerprint, and random tail.

Generated on your device. Nothing is uploaded.

How to generate CUIDs online

  1. Set the amount

    Enter how many CUIDs you need, anywhere from 1 to 1000. A batch appears as soon as the page loads and updates the moment you change the count.

  2. Pick the format

    Keep the standard 25-character form, or switch to the shorter slug variant for tidier, user-facing URLs.

  3. Copy the batch

    Copy to clipboard grabs every CUID, one per line, and Regenerate rolls a fresh batch while the counter keeps advancing so nothing repeats.

Why use this tool

Built from four parts

Each ID begins with the letter c, then packs a base36 timestamp, an in-session counter, a short fingerprint, and a block of randomness into one string.

Counter avoids clashes

A running counter advances on every ID and every regenerate, so two values created in the same millisecond are still guaranteed to differ.

URL-safe and lowercase

The base36 alphabet means every CUID drops straight into a URL, a filename, or an HTML attribute with no escaping and no uppercase to normalise.

Standard or short form

Generate the full 25-character CUID for database keys, or a compact slug of roughly 7 to 10 characters where length matters.

Up to 1000 at a time

One field controls the batch size, so seeding a table or a spreadsheet column takes a single copy instead of a thousand clicks.

Generated on your device

CUIDs are created locally in the browser tab, never fetched from a service, so no one else sees them and there is no rate limit.

About this tool

This CUID generator builds collision-resistant identifiers entirely in your browser. Each ID starts with the letter c, then packs a base36 timestamp, an in-session counter, a short fingerprint, and a block of secure randomness into one compact, URL-safe string. The timestamp and counter make IDs from the same tab monotonic, while the random tail keeps them from clashing, so a CUID works well as a database key, an event ID, or a stored file name without a central sequence to hand out numbers.

Set a count from 1 to 1000 and the batch appears the moment the page loads, updating instantly when you change the amount or switch between the standard 25-character form and the shorter slug variant. The counter keeps advancing across every ID and every regenerate, so two IDs from the same click never repeat. CUIDs are lowercase and URL-safe by design, which makes them a clean drop-in wherever a fully random key would otherwise scatter database inserts. If you prefer a classic 128-bit value use the UUID generator, for a tunable compact key use the Nano ID generator, and to sort strictly by time use the ULID generator.

Everything is generated locally, so the identifiers are known only to you and are never drawn from a shared server sequence. Because the fingerprint and randomness come from this one browser session, uniqueness is practically certain within your own use, but these IDs are not coordinated across separate machines, so treat them as collision-resistant rather than globally guaranteed. To read the embedded time back out of an ID, the Unix timestamp converter turns the millisecond value into a date.

Frequently asked questions

What is a CUID?
A CUID is a collision-resistant identifier designed for the web. The standard form is 25 lowercase characters that begin with the letter c and encode a timestamp, an incrementing counter, a session fingerprint, and a block of randomness, all written in base36 so the value is URL-safe.
How is a CUID different from a UUID?
A random UUID (version 4) is 128 bits of pure randomness written as 36 hyphenated hex characters. A CUID is shorter, lowercase, URL-safe, and starts with a timestamp and a counter, so IDs made in sequence are monotonic rather than scattered, which is friendlier to database indexes.
How are these CUIDs generated?
The timestamp comes from your device's clock, the counter advances on every ID, the fingerprint is drawn once per session, and the random tail uses your browser's cryptographically secure random source. Generation happens entirely on your device, so nothing is fetched from a server.
Can two CUIDs collide?
Within one browser session a collision is practically impossible: the counter guarantees that even IDs created in the same millisecond differ, and the random tail separates the rest. These IDs are generated locally and are not coordinated across separate machines, so treat them as collision-resistant rather than globally guaranteed unique.
What is the short slug form?
The short format is a compact version of a CUID, roughly 7 to 10 characters, that keeps a slice of the timestamp, counter, fingerprint, and randomness. It is handy for user-facing URLs and short links where a full 25-character ID would be unwieldy.
Are the generated CUIDs sent anywhere?
No. Everything is generated locally in your browser. The values never leave your device, are never uploaded, and are not stored or logged.

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