What is the difference between UUID and ULID?

UUID v4 is fully random. ULID is lexicographically sortable and encodes a timestamp, making it useful for database indexes and chronological ordering without a separate created_at column.

Are these UUIDs cryptographically random?

UUID v4 and ULID use the Web Crypto API's getRandomValues for cryptographically secure randomness. UUID v1 uses a MAC address and clock; UUID v5 is deterministic from a name and namespace.

What format are the generated IDs?

UUIDs are 36 characters with hyphens (8-4-4-4-12). ULIDs are 26 characters in Crockford Base32 (no hyphens). Toggle uppercase and hyphens as needed.

Can I generate multiple IDs at once?

Yes. Set the count parameter to generate up to hundreds of IDs in one operation, each on a separate line.

Is UUID v1 safe to use?

UUID v1 encodes the host MAC address and clock time, which can leak machine identity and timing. Prefer v4 or ULID for privacy-sensitive contexts.

How does UUID v5 work?

UUID v5 is deterministic: given the same namespace and name, it always produces the same UUID. Useful for stable IDs derived from names (e.g. URLs, email addresses).

Générateur d'UUID / ULID

Generate UUID v1, v4, v5, and ULID identifiers. Gratuit, privé et 100% côté client.

param.versionparam.countparam.uppercaseparam.hyphens

Entrée

Essayer un exemple:

Sortie

Local only

Historique récent

Aucun historique

Utilisation

Select the version: UUID v1, v4, v5, or ULID.
Set the count of IDs to generate.
Toggle uppercase and hyphens as needed.
Copy the generated identifiers.

Tâches utilisant cet outil

Générer NanoIDs for compact unique identifiers

NanoID est un tiny, URL-sûr, unique ID generator. Smaller et faster than UUID, avec customizable alphabet et taille.

TÂCHE

Générer a cryptographically secure random password

Créer un high-entropy mot de passe utilisant un cryptographically sûr random generator, avec control sur longueur et caractère sets.

TÂCHE

Générer RSA key pair and inspect self-signed certificate fields

Créer un RSA clé pair pour testing, et understand le structure de un self-signed X.509 certificate pour local development.

TÂCHE

Générer Snowflake IDs for distributed systems

Snowflake IDs (Twitter) combine timestamp, machine ID, et sequence nombre pour unique, sortable IDs en distributed systèmes sans coordination.

TÂCHE

Générer ULIDs for time-sortable identifiers

ULID (Universally Unique Lexicographically Sortable Identifier) combines un timestamp avec random données, producing IDs ce trier par creation time.

TÂCHE

Pipelines utilisant cet outil

Generer UUID et coder en Base58

PIPELINE

Generer UUID et coder Base64

PIPELINE

Questions fréquentes

What is the difference between UUID and ULID?: UUID v4 is fully random. ULID is lexicographically sortable and encodes a timestamp, making it useful for database indexes and chronological ordering without a separate created_at column.
Are these UUIDs cryptographically random?: UUID v4 and ULID use the Web Crypto API's getRandomValues for cryptographically secure randomness. UUID v1 uses a MAC address and clock; UUID v5 is deterministic from a name and namespace.
What format are the generated IDs?: UUIDs are 36 characters with hyphens (8-4-4-4-12). ULIDs are 26 characters in Crockford Base32 (no hyphens). Toggle uppercase and hyphens as needed.
Can I generate multiple IDs at once?: Yes. Set the count parameter to generate up to hundreds of IDs in one operation, each on a separate line.
Is UUID v1 safe to use?: UUID v1 encodes the host MAC address and clock time, which can leak machine identity and timing. Prefer v4 or ULID for privacy-sensitive contexts.
How does UUID v5 work?: UUID v5 is deterministic: given the same namespace and name, it always produces the same UUID. Useful for stable IDs derived from names (e.g. URLs, email addresses).