🆔 UUID Generator ☆

Overview

UUID Generator generates unique identifiers directly in your browser: UUID v4 (128-bit random), time-based UUID v1, ULID (26 characters, sortable by creation time) and NanoID (21-character URL-safe strings). Choose how many you need, up to 1000 per click, then copy the list or download it as a .txt file. All values come from the Web Crypto API, the same cryptographically secure source your browser uses for TLS. Nothing is sent to any server, no account is required, and the tool keeps working offline. Perfect for database keys, API tokens, test fixtures and distributed systems.

Which identifier should you use

UUID v4 is fully random: the standard choice for database keys and API tokens where uniqueness matters and nothing else. UUID v1 encodes a timestamp and node, so identifiers sort roughly by creation time but can leak when they were generated. ULID is a 26-character alternative that is sortable like v1 but random enough to avoid most of the leakage, which makes it popular for event logs. NanoID trades a shorter, URL-safe form for a still-negligible collision risk, which suits short links and public identifiers.

Technical specifications

Property	UUID generator behavior
Formats	UUID v4, UUID v1, ULID, NanoID
Randomness	Web Crypto CSPRNG (cryptographically secure)
Batch size	Up to 1000 per click
Export	Copy to clipboard or download as .txt
Processing	100% client-side; nothing transmitted
Offline	Works after the first load
Cost	Free, no account, unlimited generation

Privacy: identifiers are generated, not assigned

Because values come from your browser's crypto generator, nobody, including 0Appz, sees them, cannot predict them and cannot log them. That matters when the identifiers become API keys or session tokens. Nothing is stored and the tool works offline.

Identifier tips

• Prefer v4 for secrets and keys, ULID when time-sortable IDs simplify your database.
• Do not encode secrets in UUID v1: timestamps and node data can leak.
• Use NanoID where a shorter URL-safe string is convenient.
• Keep uniqueness guarantees in the database with a unique index regardless of format.
• Never reuse a UUID as a password. It is an identifier, not a credential.

Related: browse the text tools for case conversion, counters and encoders.

Versions, entropy and database keys

Not every UUID is random, and the version matters when the identifier is used as a database key. Version 4 draws 122 random bits, which gives enough entropy that a collision is practically impossible. You would need to generate about 2.7 trillion values before a 50% chance of any collision. Version 7 packs a millisecond timestamp into the leading bits, so IDs sort roughly by creation time; that ordering keeps B-tree indexes compact and avoids the write amplification that purely random keys cause in large tables. Version 1 includes the generating device's MAC address, which leaks hardware identity and should be avoided in user-facing systems. Version 5 derives a deterministic ID from a namespace and a name, which is useful when the same input must always produce the same identifier. Outside the standard, ULIDs and KSUIDs offer the same time-ordered idea with a different encoding. Two practical notes: a UUID is an identifier, not a secret, so never use one as an API key or password-reset token without additional randomness and expiry; and storage size matters at scale, a UUID stored as text takes 36 bytes, while the binary form takes 16, which is a large difference across millions of rows. This generator runs entirely in the browser and assigns no identifier to you.