UUID Validator
Validate UUIDs and identify their version — v1, v3, v4, v5, v6, v7 or v8 — plus variant (RFC 4122 / Microsoft / NCS). Decodes embedded timestamps for v1 / v6 / v7. Bulk mode for lists. 100% private.
What is the UUID Validator?
UUID Validator parses UUIDs in every common shape — canonical hyphenated (8-4-4-4-12), braced {…}, urn:uuid: prefix and bare 32-char hex — then reports the structural validity plus the encoded version and variant. Version detection covers the full RFC 4122 set (v1 time-based, v2 DCE security, v3 MD5 name-based, v4 random, v5 SHA-1 name-based) AND the modern RFC 9562 additions (v6 reordered timestamp, v7 UNIX-time + random, v8 custom). Variant detection covers RFC 4122 / 9562 ('the variant every modern UUID library produces'), NCS legacy, Microsoft GUID and Reserved. For v1, v6 and v7, the embedded timestamp is decoded and shown both as an ISO string and as a 'how long ago' delta. A bulk mode handles up to 200 UUIDs at once (one per line) with per-line pass/fail + a downloadable TSV report. Pure functions, no network.
How to use it
- Pick Single or Bulk mode at the top.
- Paste a UUID (any common shape) or a list of UUIDs.
- Read the structural validity, version, variant and any decoded timestamp.
- In Bulk mode, download a TSV report of every line's status.
Benefits
- Detects all 8 RFC 4122 / 9562 versions — v1-v8.
- Identifies the variant: RFC 4122 / 9562, NCS legacy, Microsoft GUID, Reserved.
- Accepts every common UUID shape: hyphenated, braced, urn:uuid:, bare 32-hex.
- Decodes the embedded timestamp for v1, v6 and v7 — shown as ISO + relative time.
- Flags special values — Nil UUID (all zeros) and Max UUID (all ones, RFC 9562).
- Bulk mode validates up to 200 UUIDs per click with TSV export.
- In-tool reference card lists every version with its purpose and trade-offs.
- Runs 100% in your browser — UUIDs never leave the device.
Frequently asked questions
Which UUID versions does it detect?
All of them — v1 (time-based), v2 (DCE security), v3 (MD5 name-based), v4 (random), v5 (SHA-1 name-based), v6 (reordered timestamp, RFC 9562), v7 (UNIX time + random, RFC 9562) and v8 (custom, RFC 9562).
What does 'variant' mean?
The variant is encoded in the top bits of the 'clock-seq-hi' byte and tells you which UUID format spec was used. Modern UUIDs are 'RFC 4122 / 9562' (top bits 10). NCS / Microsoft / Reserved variants exist mostly in legacy data.
How does the timestamp decoding work?
v1 stores a 60-bit timestamp in 100-ns intervals since 1582-10-15 (UUID epoch). v6 stores the same value but rearranged for big-endian sorting. v7 stores a 48-bit ms timestamp since 1970 — way simpler. We decode all three and show the result as ISO + relative.
What's a Nil UUID?
The Nil UUID is all zeros (00000000-0000-0000-0000-000000000000) — RFC 4122 reserves it as a 'no UUID' placeholder. Many APIs use it for 'empty' values.
What's a Max UUID?
Defined by RFC 9562, the Max UUID is all ones (FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF). Symmetrical with the Nil UUID — sometimes used for 'past end' sentinels.
Can I paste a Microsoft GUID?
Yes. We accept Microsoft GUID forms (with or without braces) and identify the variant as 'Microsoft GUID'. Structurally they're identical to RFC 4122 — only the variant byte differs.
Does bulk mode handle very large lists?
Yes. The first 200 rows display in the table; the TSV download has every line. The parsing itself is O(n) and well-suited to thousands of UUIDs.
Why does v4 vs v7 matter?
v4 is purely random — best for unguessability. v7 starts with a ms timestamp so UUIDs sort lexicographically by creation time — much better for database indexes. Most new projects should use v7.
Will it tell me which library generated my UUID?
Not directly. But the version tells you broadly — Java often uses v4, Postgres often uses v4 or v7, .NET often uses v4 in 'Microsoft GUID' variant. The 'manufacturer' isn't encoded in the UUID itself.
Is anything uploaded?
No. Parsing and version detection run entirely in your browser.
What if the UUID is in upper case?
We normalise to lower-case before validating, so casing doesn't matter. The canonical output is lower-case per RFC 4122 recommendation.