Guide: UUID generator & validator
↑ Back to toolWhat is this tool?
A free, client-side UUID generator and UUID validator for developers. You can create batches of identifiers (up to 100 per run), toggle hyphenated canonical form, UPPERCASE output, and braced {xxxxxxxx-xxxx-...} style (common in Windows / .NET examples). Switch between v4 (random), v1 and v7 (time-oriented layouts), or emit the nil UUID for tests.
The validate panel checks strings against a standard 8-4-4-4-12 hex pattern with a valid version/variant nibble and shows the detected version when possible. Download results as .txt, .csv, or .json; copy single rows or the full list; use save / share / history like other Spoold tools. Nothing is sent to a server for generation—only your explicit save/share actions use document storage.
Why use a browser UUID tool?
You often need a handful of IDs for Postman collections, SQL seed scripts, Jest snapshots, or a demo row in a spreadsheet—without touching production credentials or installing a CLI.
Spoold keeps the loop tight: pick version → set batch size → apply display options → generate → export. Validation helps when logs paste mixed-case or brace-wrapped values and you need a quick yes/no before writing a migration.
UUID versions (what this page generates)
- v4 (random) — Uses
crypto.randomUUID()in supporting browsers. Default choice for opaque primary keys when you only need uniqueness, not ordering. - v1 — Time-oriented MAC-era layout; this tool uses a simplified in-browser construction suitable for fixtures—not a substitute for a spec-accurate v1 from your OS or database driver.
- v7 — Time-ordered UUID (48-bit Unix ms + random); handy when you want roughly increasing sort keys without leaving the UUID type. Confirm your storage layer and drivers accept v7 before relying on it in production.
- Nil —
00000000-0000-0000-0000-000000000000sentinel for “missing” or reset tests.
v3 / v5 (name-based, namespace + hash) and v6 are not generated here—use your language's standard library when you need deterministic UUIDs from a namespace and name.
Format options
- Hyphens — Canonical 36-character string vs 32 hex digits only (some APIs accept both).
- Uppercase — Matches tools and docs that expect
A-Fin uppercase. - Braces — Wraps the value for COM-style / registry copy-paste workflows.
Validate & export
Paste a candidate line (with or without braces); the tool reports valid / invalid and the inferred version digit when the pattern matches. Invalid strings fail fast—trim whitespace and remove surrounding quotes from JSON literals before validating.
Exports bundle the current list for CSV import into Excel, JSON arrays for fixtures, or plain newline-separated text for shell loops. Pair with JSON format when embedding IDs into larger JSON files.
Use cases
| Scenario | How this tool helps |
|---|---|
| API mocks | Generate v4 rows for example responses and error objects. |
| DB fixtures | Batch-create IDs, export CSV/JSON, paste into seed SQL or ORM factories. |
| Log triage | Validate IDs copied from support tickets or tracing UIs. |
| Documentation | Consistent sample UUIDs in README tables and OpenAPI examples. |
Keyboard shortcuts
- Ctrl / Cmd + Enter — Generate (when focus is not inside an input or textarea).
- Escape — Close history or save modal.
Best practices
- Production writes — Prefer database defaults (
gen_random_uuid()in PostgreSQL, server-side UUID libraries) so IDs are not predictable from the client and survive offline-first edge cases. - Security-sensitive tokens — Do not use time-leaky v1-style IDs where unpredictability matters; v4 or dedicated crypto tokens are safer.
- Case sensitivity — UUID string equality is usually case-insensitive, but some stores normalize to lowercase—pick one convention per project.
How to use
- Choose version (v4, v1, v7, or nil) and set batch count (1–100).
- Toggle hyphens, uppercase, and braces to match your target system.
- Click Generate or press Cmd/Ctrl+Enter from outside inputs.
- Copy one line, copy all, or download TXT / CSV / JSON.
- Switch to the validate area to check pasted IDs from logs or tickets.
FAQ
Is a UUID the same as a GUID?
Yes—GUID is Microsoft’s name for the same 128-bit layout. Braced uppercase strings are a common GUID presentation.
Are v4 UUIDs unique enough?
Collision probability is astronomically low for random v4s at typical app scale. Uniqueness guarantees still come from your storage (unique indexes) and process.
Why does v1 differ from another tool?
v1 includes clock sequence and node bits; simplified browser generators may not match libuuid bit-for-bit. Use v4 when you need identical semantics everywhere, or generate v1 from your server library for production.
Can I paste multiple UUIDs to validate?
The validator is aimed at one string at a time. For bulk checks, split lines in a text editor or script first.
ULID or KSUID instead?
Sortable string IDs (ULID, KSUID) trade length and charset for lexicographic order. Use them when logs or filenames benefit from time clustering; use UUID when your stack already standardizes on RFC IDs.
Related terms
Core: uuid generator online, guid generator, random uuid v4 generator, bulk uuid generator free, uuid validator online, check if string is uuid, uuid lowercase uppercase, braced guid format.
Versions: uuid v7 generator, time ordered uuid, uuid v1 vs v4 vs v7, nil uuid 00000000, uuid version nibble, rfc 4122 uuid.
Export: uuid to json array download, uuid csv export, copy all uuids clipboard, postgresql uuid seed data.
Alternatives: sortable unique id ulid ksuid (different string format and sort properties), snowflake id generator (awareness). This page stays focused on RFC UUID strings.
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Conclusion
Spoold's UUID generator and validator fits early-stage development: fast batches, flexible string formatting, exports, and validation—with clear limits for cryptographic or database-authoritative workflows. Keep generating here; keep persisting there.