ULID Generator

The ULID Generator creates Universally Unique Lexicographically Sortable Identifiers, a modern alternative to UUIDs that combines a millisecond timestamp with strong randomness in a compact, twenty-six character string. Because the timestamp comes first, ULIDs sort naturally in the order they were created, which makes them ideal for database keys, log entries and any record where chronological ordering matters as much as uniqueness.

Each ULID is encoded with Crockford base32, an alphabet that deliberately excludes the ambiguous characters I, L, O and U so the identifiers stay readable and are far less likely to be mistyped when copied by hand. The first ten characters encode a forty-eight bit timestamp, and the remaining sixteen characters carry eighty bits of randomness, giving an astronomically small chance of collision even when many identifiers are produced in the same instant.

Everything is generated locally in your browser using JavaScript and a cryptographic random source when one is available. Nothing is uploaded, queued or logged, so you can safely produce identifiers for confidential systems, prototypes or production seed data without any of it leaving your device. Choose how many ULIDs you need and they appear instantly, ready to copy or download.

Features

• Produces standard twenty-six character ULIDs that are fully compatible with common ULID libraries across languages.
• Encodes a millisecond timestamp in the first ten characters so identifiers sort in creation order by default.
• Uses Crockford base32 which omits the confusing letters I, L, O and U to keep identifiers legible and safe to type.
• Guarantees monotonic ordering within a single batch, incrementing the random component when the timestamp repeats.
• Draws randomness from the browser cryptographic generator when present, falling back gracefully when it is not.
• Lets you generate anything from a single identifier to a thousand at once for seeding tables or load testing.
• Runs entirely offline in your browser with no sign-up, no rate limits and no data ever sent to a server.

How to use ULID Generator

1. Set the count option to the number of ULIDs you want the tool to generate in this batch.
2. Read the generated identifiers in the output panel, where each ULID appears on its own line.
3. Copy the whole block to your clipboard or download it as a plain text file for use in your project.
4. Notice that identifiers created in the same millisecond stay strictly ordered thanks to monotonic generation.
5. Regenerate at any time to obtain a fresh batch with an updated timestamp prefix reflecting the current moment.

Benefits

• Database engineers get primary keys that sort chronologically, improving index locality compared with random UUIDs.
• Developers building distributed systems avoid coordination because each node can mint unique identifiers independently.
• Teams debugging logs can eyeball ULIDs and immediately tell which event happened first from the sortable prefix.
• QA and data teams seed realistic test records quickly by generating hundreds of ordered identifiers at once.
• Anyone handling sensitive schemas keeps identifiers private because generation is entirely local to the browser.
• Product builders adopt a compact, URL-safe identifier that reads more cleanly than a hyphenated UUID string.

ULIDs are a practical middle ground between an auto-incrementing integer and a fully random UUID. The integer gives you ordering but leaks how many records exist and requires a central sequence, while a random UUID hides that information but destroys locality in database indexes. A ULID keeps the useful ordering of a timestamp while adding enough randomness that the identifier cannot be guessed or enumerated in practice.

The monotonic behaviour in this tool matters when you generate many identifiers faster than the clock ticks. Rather than producing several ULIDs that share a timestamp but sort unpredictably, the generator increments the random field so every identifier in the batch is strictly greater than the one before it. That property is exactly what the ULID specification recommends for high-throughput generation.

Because the tool runs locally, it is well suited to generating seed data, fixtures and example keys for documentation without exposing anything. Keep in mind that the timestamp portion reveals roughly when an identifier was created, so if that is sensitive in your context you may prefer an opaque random identifier instead. For most application keys, however, the visible ordering is a feature rather than a drawback.