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GET https://digitalgreenhouse.com.au/api/tools/uuid-generatorversion— string, one ofv4|v7|ulid, defaultv4. v4, v7 or ulid. Also accepted astype.count— integer, default1. How many.uppercase— boolean, defaultfalse. Upper-case UUIDs (ULIDs are always upper-case).
The API answers from our server, and our code doesn’t store what you send. Fair-use limits apply. API guide · all endpoints (JSON) · OpenAPI
UUID v4, v7 and ULID — what’s the difference?
A UUID (Universally Unique Identifier) is a 128-bit value you can generate anywhere with near-zero chance of a collision — perfect for database keys, file names and request IDs without a central counter.
- UUID v4 is fully random. Simple and ubiquitous, but the random ordering means new rows scatter across a database index.
- UUID v7 puts a millisecond timestamp at the front, so IDs sort roughly in creation order. That’s much friendlier to database indexes while staying globally unique — it’s the modern recommendation for new systems.
- ULID packs the same idea (time + randomness) into a shorter, case-insensitive 26-character string using Crockford Base32 — nice when you want something more compact and URL-friendly.
Are these really unique?
For practical purposes, yes. With 122 bits of randomness in a v4 UUID you’d need to generate billions per second for many years before a collision became likely.
Which should I use for a new database?
UUID v7 or ULID, because the time-ordering keeps inserts fast and the data naturally sortable. We help teams pick and implement these as part of custom development.