How it works
- 1
Choose a UUID version or ULID
UUID v4 is random and the most widely used. UUID v7 is sortable by time — ideal for database primary keys. UUID v5 is deterministic (same inputs → same output). ULID is a URL-safe, time-sortable alternative.
- 2
Set count and format
Generate 1 to 100 IDs at once. Format options: standard dashes, no dashes, uppercase, or curly braces. Copy individual IDs or all at once.
- 3
Copy and use
Click Copy on any result to add it to your clipboard instantly. The annotated bit breakdown explains which parts of the UUID encode which information.
46c07db1-a86a-463d-abc3-fd21e52fe2d2Bit breakdown
🛡️ Verify zero uploads — open DevTools → Network tab
Open your browser's DevTools (F12), go to the Network tab, and use this tool. You will see zero outbound requests — all processing runs inside your browser sandbox via WebAssembly or pure JavaScript. Nothing you paste or upload is ever sent anywhere.
Use cases
Database primary keys
Use UUID v7 or ULID as primary keys to get collision-free distributed IDs that sort chronologically. Avoids the performance problems of random UUID v4 with B-tree indexes.
Session and token generation
Use UUID v4 for session IDs, CSRF tokens, one-time links, and API keys — the randomness makes them safe to use in security contexts.
Content-addressable IDs with UUID v5
Use UUID v5 with a URL namespace to generate a stable, deterministic ID for any resource URL. The same URL always produces the same UUID, making it useful for deduplication.
Frequently Asked Questions
Which UUID version should I use?
Use v4 when you need a random ID and don't care about sorting. Use v7 for database primary keys — the timestamp prefix keeps index pages sequential and avoids fragmentation. Use v5 when you need a deterministic ID derived from a known input (like a URL or domain name). Use ULID as a URL-safe alternative to v7.
Are the UUIDs generated here cryptographically secure?
UUID v4 and v7 use crypto.getRandomValues() — the same CSPRNG used by Web Crypto API. This is cryptographically secure and suitable for tokens and session IDs.
Can I use UUID v7 as a primary key in PostgreSQL / MySQL?
Yes — both PostgreSQL (uuid type) and MySQL (CHAR(36) or BINARY(16)) support UUID v7. Because the first 48 bits are a timestamp, new rows cluster naturally in the index, avoiding the random-write amplification you get with UUID v4.
What is the difference between UUID and ULID?
Both are 128-bit identifiers. ULID uses Crockford Base32 encoding (26 characters, URL-safe, case-insensitive) while UUID uses hex with dashes (36 characters). ULIDs are naturally sortable like UUID v7. Choose ULID when you want a shorter, URL-safe representation; choose UUID v7 when you need RFC 9562 compatibility.
Is this tool sending my UUIDs anywhere?
No. All UUIDs are generated in your browser using the Web Crypto API and the uuid/ulid JavaScript libraries. No requests are made — you can verify this in DevTools → Network.
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