UUID & ULID Generator
Generate unique identifiers instantly.
Generating IDs for your jobs?
Every job and cron in Recuro gets a unique ID. Track executions, retries, and logs with built-in identifiers.
What are UUIDs?
A UUID (Universally Unique Identifier) is a 128-bit value used to identify information without
requiring a central authority. UUID v4, the most common version, generates identifiers using
random or pseudo-random numbers. The format is 8-4-4-4-12 hexadecimal characters, like
550e8400-e29b-41d4-a716-446655440000.
ULIDs (Universally Unique Lexicographically Sortable Identifiers) improve on UUIDs by encoding a millisecond-precision timestamp in the first 48 bits. This makes them sortable by creation time while retaining the same 128-bit uniqueness guarantee. They use Crockford's Base32 encoding for a compact, URL-safe 26-character string.
Nano IDs are shorter identifiers with a configurable alphabet and length. The default 21-character Nano ID with 64 alphabet characters provides roughly the same collision resistance as UUID v4. They are popular for URL slugs and user-facing identifiers where brevity matters.
Using unique IDs for correlation in scheduled jobs? Recuro tracks every execution with unique IDs, full request/response logging, and retry management.
Frequently Asked Questions
What's the difference between UUID and ULID?
UUID v4 values are fully random 128-bit identifiers formatted as 8-4-4-4-12 hex characters. They are universally supported but not sortable by creation time. ULIDs are also 128 bits but encode a millisecond timestamp in the first 48 bits, making them lexicographically sortable by creation time — useful for database primary keys and time-ordered data.
Are these cryptographically secure?
Yes. All IDs are generated using crypto.getRandomValues(), the same cryptographically secure pseudorandom number generator (CSPRNG) that browsers use for TLS. No Math.random() is involved.
Can UUIDs collide?
In theory, yes — any random value can repeat. In practice, UUID v4 has 122 random bits, yielding 5.3 x 10^36 possible values. You would need to generate about 2.7 x 10^18 UUIDs to have a 50% chance of a single collision. For all practical purposes, collisions are impossible.
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