1. What does this tool do
This free online UUID generator creates one or more UUID v4 values instantly. Use it for generate UUID, unique ID generator, or UUID v4 for development, testing, or databases. Get standard format (with hyphens) or compact (no hyphens)—no sign-up, no server. All generation runs in your browser. Ideal for development, database primary keys, APIs (request IDs, correlation IDs), or testing.
2. How to use it
Quick start: Set count (e.g. 1, 5, 10), choose standard or compact format, click Generate, then copy one or all UUIDs for your app, database, or config.
- Set count — Choose how many UUIDs to generate (e.g. 1, 5, 10).
- Choose format — Standard (e.g. 550e8400-e29b-41d4-a716-446655440000) or compact (no hyphens).
- Generate — Click the button (or the tool generates on load). New UUIDs appear in the list.
- Copy — Copy one or all UUIDs for use in your app, database, or config.
3. How it works
UUID v4 uses 122 random bits (the rest are version and variant bits). The tool uses crypto.getRandomValues() (or a fallback) to fill those bits and formats the result as a UUID string. All generation is client-side in your browser; no server is involved. No data is sent to any server.
4. Use cases & examples
- Development — Quick unique IDs for entities, logs, or test data.
- Database — Generate primary keys or external IDs before insert.
- APIs — Request IDs, correlation IDs, or trace IDs in UUID form.
- Testing — Create a set of UUIDs for fixtures or mocks.
Example
- Generate 1 → e.g. a1b2c3d4-e5f6-4789-a012-3456789abcde.
- Generate 5, compact → five 32-character hex strings without hyphens.
5. Limitations & known constraints
- v4 only — The tool generates random UUIDs (v4). It does not produce time-based (v1) or namespace-based (v3/v5) UUIDs unless the tool adds that.
- Uniqueness — Collision probability is negligible for normal use; for extreme scale, consider additional guarantees in your system.
- No persistence — Generated UUIDs are not stored by the tool; copy them if you need to keep them.