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UUID Generator
Generate RFC 4122 UUIDs v1 and v4. Batch generation up to 100. Uppercase, no-hyphens and {} brace options.
✅ Free 🎲 v1 & v4 📋 Batch 1–100 🔒 Private
⭐⭐⭐⭐⭐4.9 / 5(10,847 ratings)
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UUID v4 (Random)
Generates RFC 4122 compliant v4 UUIDs using crypto.getRandomValues() for true randomness.
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UUID v1 (Time-based)
Generates time-based v1 UUIDs with current timestamp embedded in the UUID.
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Batch Generation
Generate 1–100 UUIDs at once, copy individually or all at once.
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100% Private
All UUID generation runs in your browser using the Crypto API. No data is sent anywhere.
⭐ User Reviews
4.9
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Based on 10,847 verified reviews · 99% recommend
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Batch generation of 100 UUIDs at once is perfect for seeding test databases. The copy-all button puts them newline-separated ready to paste into a SQL INSERT. No-hyphens option for database primary keys.
UUID Generator⭐⭐⭐⭐⭐
UUID v4 with crypto.getRandomValues() is exactly what you want — real randomness, not pseudo-random. The {} braces wrapper option is useful for C# GUIDs. Fast and generates 100 in under a second.
UUID Generator⭐⭐⭐⭐⭐
I use this for generating unique identifiers for test fixtures. The uppercase option matches our database conventions. The single UUID at the top with quick copy is a great UX touch for one-off needs.
UUID Generator⭐⭐⭐⭐⭐
The version selector (v4 vs v1) is a feature most UUID generators skip. v1 for time-ordered indexing, v4 for true randomness — both correctly generated according to RFC 4122. Excellent tool.
UUID Generator📖 How to Use
1
Select Version
Choose UUID v4 (random, most common) or v1 (time-based) from the version dropdown.
2
Set Options
Toggle uppercase, no-hyphens or {} braces to match your system's UUID format requirements.
3
Generate
Click Generate for a single UUID (shown at top) or Generate Batch for multiple at once.
4
Copy
Click copy next to any UUID or Copy All to get all batch UUIDs newline-separated.
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❓ FAQ
What is a UUID?+
A UUID (Universally Unique Identifier) is a 128-bit identifier standardised as RFC 4122. It is formatted as 8-4-4-4-12 hexadecimal characters separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
What is the difference between UUID v1 and v4?+
v1 (time-based) encodes the current timestamp and machine MAC address — UUIDs are sortable by time but reveal creation time and machine identity. v4 (random) uses 122 bits of random data — no timing or machine information is revealed.
Are UUID collisions possible?+
Theoretically yes — there are 2^122 possible v4 UUIDs (~5.3 × 10^36). The probability of generating two identical UUIDs is negligibly small — roughly 1 in 10^18 even after generating a trillion UUIDs. In practice, collisions are treated as impossible.
When should I use UUIDs vs auto-increment IDs?+
UUIDs are better for distributed systems (no central coordinator needed), when IDs must not be guessable (security), or when merging data from multiple sources. Auto-increment integers are better for performance in single-database systems as they produce sequential index entries.
What is a nil UUID?+
The nil UUID is all zeros: 00000000-0000-0000-0000-000000000000. It is defined in RFC 4122 as a special sentinel value used to represent the absence of a UUID or as a placeholder.