UUID/ULID Generator

Unique identifiers are everywhere: database primary keys, correlation IDs in logs, file names, and API resources. When you need a quick set of safe identifiers, generating them locally is faster than writing a script and avoids dependency mismatches. This page generates UUID v4 and ULID with one click and lets you copy them as a list.

UUID v4 is purely random (122 bits of randomness) and is widely supported across databases and libraries. It’s a solid default when you only need uniqueness and don’t care about ordering. ULID adds a time component (milliseconds) plus randomness, producing identifiers that sort roughly by creation time. That can be helpful for log streams, event tables, and systems where ordered inserts reduce index fragmentation.

Neither UUID nor ULID is meant to be secret. They are identifiers, not authentication tokens. Don’t use them as passwords or API keys. If you expose IDs publicly, consider whether sequential or time-ordered IDs leak business metadata. For many internal workflows, though, UUID and ULID are a reliable, ergonomic choice.

If you ever worry about collisions, remember that the probability is extremely low for realistic usage. The main practical pitfalls are formatting and normalization: storing UUIDs with/without hyphens, upper/lowercase in text systems, or accidentally truncating IDs. Use the output exactly as generated and you’ll stay consistent across environments.