UUID Generator

Generate UUID v1, v4, and v7 identifiers in bulk — using crypto-random browser APIs.

UUID Generator

Client-side

About this tool

UUIDs (Universally Unique Identifiers) are 128-bit identifiers formatted as 32 hexadecimal characters separated by hyphens: xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx. This generator produces v1 (timestamp-based), v4 (random), and v7 (sortable timestamp+random) UUIDs in quantities from 1 to 1000.

UUID v4 is the most common choice for application IDs: it contains 122 bits of cryptographic randomness (sourced from the browser's crypto.getRandomValues), giving a collision probability so low it can be treated as zero for all practical purposes. UUID v7 is a newer format (RFC 9562) that is timestamp-prefixed, making it naturally sortable — useful for database primary keys where index locality matters. UUID v1 embeds the current timestamp and a node identifier.

All generation uses browser-native randomness. Nothing leaves your browser. Generated IDs can be copied individually or as a batch (newline-separated). Use the count slider to generate up to 1000 at once for seeding test fixtures or database migrations.

FAQ

Are the generated UUIDs truly unique?

For v4, the probability of generating two identical UUIDs in your lifetime of computing is astronomically small (roughly 1 in 2^122). They are safe to use as globally unique IDs without coordination.

What is UUID v7 and when should I use it?

UUID v7 (RFC 9562) encodes the current Unix timestamp in milliseconds in the first 48 bits, followed by random bits. This makes v7 UUIDs sortable by creation time when used as database primary keys, improving B-tree index locality and query performance compared to random v4 UUIDs.

Should I use UUID or ULID?

Both are valid. ULIDs are 26-character Crockford Base32 strings that are also timestamp-sortable and slightly more compact than UUIDs. UUIDs have broader ecosystem support. Use ULIDs if you prefer a URL-safe, case-insensitive, sortable format; use UUIDs for maximum compatibility.