Bulk ULID Generator
Generate Universally Unique Lexicographically Sortable Identifiers (ULID) directly in your browser. The modern, URL-safe alternative to standard UUIDs.
Limitations & Specifications
- Max Generation: 1,000 ULIDs per click to prevent memory overload in the browser.
- Environment: Requires a modern browser supporting the
crypto.getRandomValuesAPI for true cryptographic entropy. - Format Output: Guaranteed 26 characters, Crockford Base32 encoding (No dashes, strictly alphanumeric).
How to Use
- Specify Quantity: Enter the amount of ULIDs you need generated in bulk.
- Generate: Click 'Generate ULIDs'. The generation happens purely locally on your device for absolute security.
- Export: Use the 'Copy All' button for clipboard transfer, or 'Download' to save the list directly to a text file.
Why Developers are Switching to ULID
Premise: Generating standard UUIDv4 primary keys introduces a performance bottleneck in large-scale databases. Because UUIDv4 is random, inserting new rows forces databases to re-balance B-tree indexes, causing fragmentation and high write latency.
Evidence: ULID (Universally Unique Lexicographically Sortable Identifier) solves this by replacing the random layout with a time-ordered structure. The first 48 bits encode the creation time in milliseconds, while the remaining 80 bits provide cryptographic randomness. Its Crockford Base32 encoding also makes it shorter (26 characters) and URL-safe.
Conclusion: If you are building a modern architecture, using a ULID generator keeps your identifiers universally unique without sacrificing database index performance. It serves as a drop-in replacement for traditional identifiers.
Frequently Asked Questions
ULID vs UUID: Which is better for databases?
For database indexing (especially B-trees in PostgreSQL or MySQL), a ULID is almost always better than a standard UUIDv4. Because ULIDs are lexicographically sortable by time, database inserts happen sequentially, leading to significantly better write performance and eliminating massive index fragmentation.
What is the format of a ULID?
A ULID is exactly 26 characters long, encoded in Crockford's Base32. It consists of a 48-bit timestamp (millisecond precision) followed by 80 bits of cryptographic randomness. This makes it compact and URL-safe, avoiding the hyphens used in traditional 36-character UUIDs.
Are ULIDs case sensitive?
No. ULIDs use Crockford's Base32 encoding, which excludes ambiguous characters like I, L, O, and U to prevent human transcription errors. It is case-insensitive, though they are canonically represented and generated in uppercase.