There is no universally best identifier, only the right fit. Here is a short decision framework for choosing between UUID, ULID and Nano ID for your next system.
Start from requirements, not fashion
Every popular identifier scheme is 128 bits of uniqueness dressed differently. The right choice falls out of four questions: Do you need time ordering? How short must the text form be? How important is standardization and native database support? And does the identifier need to hide when it was created? Answer those and the decision is usually obvious.
The three contenders
UUID is the universal standard: 36 characters, native database types, understood by every tool. UUID v7 adds time ordering; v4 stays fully random. ULID is a 26-character, Base32, time-sortable identifier designed for readable, URL-friendly keys. Nano ID is a compact, configurable random string, 21 characters by default, popular for short public IDs where you control both ends.
| Need | Best fit |
|---|---|
| Maximum compatibility and native DB type | UUID (v7 or v4) |
| Time-ordered keys, standard tooling | UUID v7 |
| Short, sortable, readable string | ULID |
| Shortest URL-friendly public ID | Nano ID |
| Hide creation time | UUID v4 or Nano ID |
A recommendation for most teams
For a typical application in 2026, use UUID v7 for internal primary keys and UUID v4 where you must not leak timing. That keeps you on the standard, gives you native database types, and delivers the ordering benefit that first drew people to ULID. Reach for ULID or Nano ID only when a shorter or more readable string is a genuine product requirement and your stack handles it cleanly.
Whichever you choose, keep the fundamentals
Use a cryptographic random source, enforce uniqueness in the database, normalize storage format, and never treat the identifier as a secret. The scheme matters less than getting those four right. You can generate and inspect UUIDs with the tools on this site to prototype before committing.