True Random UUID Generator - Bulk v4 & v7 UUIDs Online

A UUID (universally unique identifier, also called a GUID on Windows platforms) is a 128-bit value written as 32 hexadecimal digits in five hyphen-separated groups, following the pattern xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx, where M encodes the version and N encodes the variant. Because the value space is astronomically large, two properly generated UUIDs will, for every practical purpose, never collide — which is why they are the default choice for database primary keys, API request IDs, file names, distributed tracing, message deduplication, and any situation where independent systems must mint identifiers without coordinating with each other. This UUID generator runs entirely in your browser. Every identifier is built from crypto.getRandomValues(), the cryptographically secure random source provided by the Web Crypto API, rather than the predictable Math.random(). Nothing you generate is sent to a server, logged, or stored: close the tab and the identifiers exist only where you pasted them. That makes the tool safe to use even for identifiers that will end up in production systems. Two versions are supported, both defined by RFC 9562 (which obsoleted the original RFC 4122 in 2024). Version 4 is the classic fully random UUID: apart from six fixed version and variant bits, all 122 remaining bits are random. Version 7 is the modern time-ordered alternative: its first 48 bits hold the Unix timestamp in milliseconds, followed by random bits. Because the timestamp comes first, v7 identifiers created later sort lexically after earlier ones. That single property makes them dramatically friendlier to database indexes — B-tree pages fill sequentially instead of being written to at random — so v7 is now the recommended default for new primary keys in PostgreSQL, MySQL, and most other stores. Choose v4 when you specifically do not want identifiers to reveal creation time. The bulk option produces up to 1,000 identifiers at once, one per line, ready to paste into a seed script, spreadsheet, or test fixture. Formatting toggles convert the output to uppercase (both cases are equally valid per the specification, which recommends emitting lowercase) or strip the hyphens for systems that store the bare 32-digit form. One honest limitation: uniqueness is probabilistic, not registered — no generator can guarantee that an identifier was never used elsewhere, and UUIDs are identifiers, not secrets, so never use one as a password or access token. An optional true-random mode ties the generator to a physical source of randomness. When selected, the tool fetches eight 16-bit integers derived from atmospheric radio noise via RANDOM.ORG's public HTTP interface — your browser talks to random.org directly, with no server of ours in between — and combines them into a single 128-bit seed for the sfc32 pseudorandom generator. Every UUID in the batch then draws its random bits from that seeded generator, so the whole batch traces back to physical randomness rather than to an algorithmic state; in v7 mode the 48-bit timestamp field still comes from your clock, exactly as in local mode, and the version and variant bits are set identically. The honest trade-off: the seed is genuinely random, but the expansion into many identifiers is deterministic once seeded, and the seed integers travel over the network — perfectly fine for identifiers, which is why the local CSPRNG remains the default and an equally sound choice. If random.org is unreachable or its per-IP quota is exhausted, the tool automatically falls back to crypto.getRandomValues(), shows a note saying so, and the source badge under the results always states which path actually produced your identifiers.