UUID Generator
Generate UUID v1 (time-based), v4 (cryptographically random), or v5 (SHA-1 name-based) — one at a time or in bulk. Output in standard, UPPERCASE, no-hyphens, or braces format. One-click copy. Pro: generate up to 100 at once.
Real-World Use Cases
1. Database Seed Scripts
You're writing a seed script for a PostgreSQL database and need 20 unique primary keys. Generate 20 UUID v4 values in bulk, copy the list, and paste them into your SQL INSERT statements.
Settings
Version: v4 (random) Count: 20 Format: standard (lowercase)
Output (first 3)
a3f1d2e8-7b4c-4a1e-9f3d-2c8b5a6e7f01 b7e2c9d4-3a5f-4e8b-a1c6-8d9f0e7b2a43 c5d8a1f3-6e9b-4c2d-b7a0-1f4e3d8c5b92
2. Deterministic IDs with UUID v5
You need the same ID every time for a given user email — useful for idempotent imports or deduplication. UUID v5 generates a deterministic UUID from a namespace + name, so "[email protected]" always produces the same UUID.
Input
Version: v5 (name-based SHA-1) Namespace: URL Name: [email protected]
Output (always the same)
5c1c48a3-7f3a-5a12-b2e9-4f8d6c0e1b7a
3. API Testing with Unique Request IDs
When load-testing an API, each request needs a unique X-Request-ID header. Generate 100 UUIDs in no-hyphens format, then feed them into your test script (k6, Artillery, or cURL).
Settings
Version: v4 Count: 100 Format: no-hyphens
Output (first 3)
a3f1d2e87b4c4a1e9f3d2c8b5a6e7f01 b7e2c9d43a5f4e8ba1c68d9f0e7b2a43 c5d8a1f36e9b4c2db7a01f4e3d8c5b92
How to Use — Step by Step
- Choose a version — Select v1 for time-ordered IDs, v4 for fully random IDs (most common), or v5 for deterministic name-based IDs.
- Set quantity — Enter how many UUIDs you need (1–100). Bulk generation is useful for seed scripts and test data.
- Pick a format — Standard (
8-4-4-4-12), UPPERCASE, no-hyphens, or braces ({...}) for GUID-style systems like .NET. - Generate — Click the generate button. All UUIDs are created instantly using your browser's
crypto.getRandomValues()for cryptographic randomness. - Copy — Click copy to get the full list. Paste into your SQL file, JSON fixture, or test script.
Frequently Asked Questions
What is a UUID and when should I use one?▼
A UUID (Universally Unique Identifier) is a 128-bit identifier that is guaranteed to be unique across space and time. Use UUIDs as primary keys in databases, session tokens, API request IDs, or any time you need a unique identifier without a central authority.
What is the difference between UUID v1, v4, and v5?▼
UUID v1 is time-based (includes timestamp and MAC address). UUID v4 is completely random using cryptographic randomness — the most common choice. UUID v5 is deterministic, generated from a namespace and a name using SHA-1, so the same inputs always produce the same UUID.
Is UUID v4 truly unique?▼
Practically yes. UUID v4 has 122 random bits, giving 5.3 × 10^36 possible values. The probability of a collision is astronomically low — you'd need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of one duplicate.
What is the difference between UUID and GUID?▼
They are the same thing. UUID is the official term from RFC 4122. GUID (Globally Unique Identifier) is Microsoft's name for the same concept. Both use the same 8-4-4-4-12 hex format.
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