UUID Generator

UUID Generator v4 — free online

Generate cryptographically random UUID v4 values in your browser. Single IDs or bulk lists — copy with one click.

Use the tool

Full tool — runs in your browser. No sign-up required.

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Full guide: Hash generators — SHA, MD5 and bcrypt More in Free security & crypto tools

Need a UUID v4 for a database primary key, test fixture or mock API response? Tentaco generates RFC 4122 version-4 identifiers using crypto.getRandomValues in your browser — no round trip to a server, no account, no rate limits on basic use.

Some online UUID sites generate IDs server-side and may log requests. For production systems that is unnecessary attack surface; for tests it is simply slower. Tentaco creates IDs locally so seeds and sequences never leave your tab. Generate one UUID, copy it, or produce bulk lists for load tests and seed scripts.

UUID v4 uses random bits with correct version and variant fields. You can also explore v1 time-based IDs when ordering matters. Output is plain text — paste into SQL, JSON, YAML or your ORM migration. Works offline after first visit.

Compare with rolling your own Math.random() — that is not UUID-compliant or cryptographically secure. Compare with uuid npm package — same result without node installed. Bookmark for daily dev work.

Why use this tool?

UUID v4 instantly
Copy with one click
No sign-up

How it works

Click «Open tool» to open the UUID Generator.
Choose UUID v4 (random) or v1 (time-based) if offered.
Click generate for a single ID, or set a bulk count for test data.
Copy one UUID or the full list to clipboard.

Common use cases

Primary keys in prototypes before UUID columns exist in schema
Bulk fixtures for integration tests (100+ unique IDs)
Mock REST responses and OpenAPI examples
Quick unique filenames or correlation IDs in logs

Tips & comparisons

1vs uuidgenerator.net and similar: server-generated IDs may be logged. Tentaco uses local crypto APIs.
2vs Python uuid.uuid4() / Node uuid: no terminal needed — copy from browser on any device.
3vs PostgreSQL gen_random_uuid(): use when you need IDs before touching the database.
4Security note: v4 from crypto.getRandomValues is suitable for keys; do not use Math.random() substitutes.

Privacy & data handling

Transfer to Tentaco: No for the standard mode. Processing: local in the browser. Permanent storage: only if you copy or save the result yourself.

LocalThis tool processes data locally in your browser. Tentaco does not receive your file contents for this mode.

File transfer: No — files stay on your device
Processing: Locally in the browser
External APIs: None for this tool
Temporary storage: Browser memory only while the tab is open
Permanent storage: Only if you download or save the result yourself

UUID Generator v4 — free online

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Frequently asked questions

Are UUIDs generated on a server?

No. IDs are created locally with crypto.getRandomValues in your browser.

Is UUID v4 cryptographically secure?

Yes — v4 uses secure random bytes suitable for database keys and session identifiers in typical apps.

Can I generate many UUIDs at once?

Yes. Bulk mode creates long lists for tests; copy the entire block in one action.

What is the difference between v4 and v1?

v4 is random. v1 embeds timestamp and MAC-derived node info — useful when sortable creation time matters.

Do I need an account?

No. Generate and copy immediately without sign-up.

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