Are UUIDs truly unique?

UUIDv4 contains 122 random bits, giving a collision probability so low it is negligible for all practical purposes, even generating billions of IDs.

What is the difference between UUIDv4 and UUIDv7?

UUIDv4 is purely random. UUIDv7 embeds a millisecond-precision timestamp in the first bits, making UUIDs sortable by creation time — useful for database indexes.

Can I use these UUIDs in production?

Yes. The generator uses the browser's cryptographic PRNG (crypto.getRandomValues), which is suitable for production-grade unique ID generation.

Best Free Online UUID Generator

Universally Unique Identifiers (UUIDs) are the standard way to generate collision-resistant IDs for database rows, distributed system events, API resources, and file names. devtoolkit.sh's UUID Generator creates cryptographically random UUIDs using your browser's native crypto.getRandomValues API, which guarantees the statistical uniqueness required for production use. You can generate a single UUID or a batch of up to 100 at once, with options for UUIDv4 (purely random, the most widely used), UUIDv1 (time-based), and UUIDv7 (time-ordered, increasingly adopted for database index performance). Output can be formatted as standard hyphenated UUIDs, uppercase, or without hyphens. All generated values can be copied to the clipboard individually or as a list. Since generation uses your browser's cryptographic random number generator, no UUIDs are predictable, and nothing is recorded or sent to a server. UUIDv7 is especially worth considering for new projects: its timestamp prefix makes UUIDs sortable by creation order, which significantly improves database index locality and query performance in systems like PostgreSQL.

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FAQ

Are UUIDs truly unique?: UUIDv4 contains 122 random bits, giving a collision probability so low it is negligible for all practical purposes, even generating billions of IDs.
What is the difference between UUIDv4 and UUIDv7?: UUIDv4 is purely random. UUIDv7 embeds a millisecond-precision timestamp in the first bits, making UUIDs sortable by creation time — useful for database indexes.
Can I use these UUIDs in production?: Yes. The generator uses the browser's cryptographic PRNG (crypto.getRandomValues), which is suitable for production-grade unique ID generation.