Tool overview
What is a UUID Generator?
A UUID generator creates and inspects universally unique identifiers (v4, v5, v7) used as primary keys, correlation IDs, and resource names.
Why use this UUID Generator?
Create bulk IDs, validate formats, and decode version/variant bits locally without calling an identity service.
Key Features
UUID v4/v5/v7, format options (braces, URN), validate/decode, bulk export, and client-side generation.
How to Use
Follow these steps to get accurate results from the tool interface above.
- Choose Create for new IDs, or Validate / Decode to inspect a pasted UUID (dashed, undashed, braces, or urn:uuid:).
- Pick a version: v4 (random), v7 (time-ordered), v5 (namespace + name), or the Nil / Max sentinels.
- Toggle format chips—hyphens, braces, URN, uppercase, quotes—to reformat the same IDs without regenerating entropy.
- Adjust quantity (1–250) and separator, then click the hero UUID to copy, or use Copy all / JSON / Download.
- Press Ctrl/Cmd+Enter to regenerate. Optional auto-copy puts the primary UUID on the clipboard after each generate.
UUID Generation Technical Specifications
Operational details for UUID versions, formatting, and decode inspection as implemented by this generator.
UUID v4 — Random 122-bit Payload
Version 4 sets the version nibble to 4 and variant bits to RFC 4122 variant 10xx. The remaining 122 bits are filled from crypto.getRandomValues(), providing CSPRNG-quality entropy in modern browsers.
Collision probability follows the birthday paradox—at 1 billion v4 UUIDs, collision odds remain negligible for application identifiers. Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where y is 8, 9, a, or b.
UUID v7 — Unix Timestamp + Monotonic Counter
UUID v7 (RFC 9562) embeds a 48-bit Unix timestamp in milliseconds in the most significant bits, followed by a 12-bit monotonic counter (rand_a) and random bits. Bulk IDs generated in the same millisecond stay lexicographically ordered.
Decode mode extracts the embedded UTC timestamp for inspection. Clock rollback on the client continues from the last seen timestamp so ordering does not reverse within a session.
UUID v5 — Namespace + Name (SHA-1)
Version 5 hashes a namespace UUID plus a UTF-8 name with SHA-1, then sets version 5 and RFC 4122 variant bits. Presets cover DNS, URL, OID, and X.500 namespaces; a custom namespace UUID is also supported.
The same namespace and name always yield the same UUID. Bulk v5 rows append -0, -1, … to the name so each line is distinct yet deterministic.
Formats, Sentinels & Decode
Output supports hyphens on/off, {braces}, urn:uuid: prefix, uppercase hex, quotes, and join separators (newline, comma, space, semicolon, pipe). Quantity ranges from 1 to 250. Nil (00000000-0000-0000-0000-000000000000) and Max (ffffffff-ffff-ffff-ffff-ffffffffffff) are available as sentinels.
Validate / Decode accepts common forms, reports version and variant, and for v7 shows the embedded timestamp. Version 1 is omitted intentionally—MAC / node identifiers are a privacy footgun in browsers; use v7 for time-ordered IDs instead. Version 3 (MD5) is omitted in favor of v5.
Frequently Asked Questions
Expandable answers for common debugging bottlenecks and data privacy questions.
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Official Documentation & References
Authoritative specifications and platform documentation for this utility.