How to Generate ULIDs Online: A Quick Developer Guide

July 6, 2026

To generate a ULID online, open the ByteTools ULID Generator, choose how many IDs you need (1–50), and click Generate — each 26-character ULID is created locally in your browser with the current timestamp and cryptographically secure randomness. No server, no account, and nothing is uploaded or stored, so the IDs are yours alone.

This guide explains what a ULID is, how to generate one in seconds, and how to read the structure so you know exactly what the tool produces.

What a ULID is

A ULID — Universally Unique Lexicographically Sortable Identifier — is a 128-bit value encoded as 26 characters in Crockford's Base32. The first 10 characters hold a 48-bit millisecond timestamp; the last 16 hold 80 bits of randomness. Because the timestamp sits at the front, ULIDs sort in creation order as plain strings, which makes them a developer-friendly alternative to random UUIDs for database keys, log lines and event IDs.

Step-by-step: generating ULIDs

Set the count. Choose how many ULIDs you want, from 1 up to 50 at a time.
Click Generate. The tool reads the current time at that moment and appends secure randomness — IDs are never precomputed at page load.
Copy what you need. Copy a single ULID, or use Copy all to grab the whole batch at once.
Regenerate freely. Click again for a fresh batch; every ULID carries a new timestamp and new random bits.

Reading a ULID

Splitting a ULID into its two halves makes its behaviour obvious.

Part	Length	Encodes	Why it matters
Timestamp	First 10 chars	48-bit millisecond time	Makes IDs sort by creation order
Randomness	Last 16 chars	80 secure random bits	Guarantees uniqueness within a millisecond

Two ULIDs generated seconds apart will share a similar prefix and sort in the order they were made — something a random UUID cannot promise.

Where the randomness comes from

The 80-bit random portion is drawn from crypto.getRandomValues, the browser's cryptographically secure random source. Combined with the millisecond timestamp, that makes the chance of a collision within the same millisecond astronomically small. Everything happens in JavaScript on your device, so the tool works offline once the page has loaded and never sends your IDs anywhere.

Putting the generated IDs to work

Once you have a batch, the ULIDs slot straight into most workflows. Paste one into a database record as a primary key, use it as an event or request identifier in a log line, or drop it into a URL — the dash-free, URL-safe alphabet means no encoding is needed. Because the format is a plain 26-character string, it fits any column type that holds text and compares cleanly.

If you are seeding a test fixture or mocking API responses, generate the full 50, hit Copy all, and paste the block directly into your file. The IDs will already sort in the order they were created, which is convenient for assertions that depend on ordering. And since none of this touches a network, you can generate as many batches as you like without rate limits or accounts.

Try the ULID Generator — free and 100% in your browser.

FAQ

How many ULIDs can I generate at once?

Between 1 and 50 per click. Set the count, generate, and use Copy all to grab the entire batch in one go — then click again for another set if you need more.

Are the ULIDs generated on a server?

No. Every ULID is created locally in your browser using the current time and secure randomness. Nothing is uploaded, logged or stored, so the tool keeps working offline and your IDs stay private.

Can I trust these for production keys?

The random bits come from the browser's cryptographically secure generator, and the format follows the ULID specification, so they are suitable for database keys, event IDs and similar production use.

Do ULIDs need dashes like UUIDs?

No. A ULID is a single 26-character string with no dashes, using a case-insensitive, URL-safe Base32 alphabet, which makes it clean to drop into URLs and identifiers.

Related free tools

UUID Generator — create classic random UUIDs.
NanoID Generator — compact URL-friendly IDs.
Base32 Encode — encode data in Base32.
JSON Formatter — tidy up JSON that holds your IDs.

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