UUID / GUID Generator
Generate cryptographically strong Version 4 UUIDs instantly.
What Is a UUID and When Do You Need One?
A UUID (Universally Unique Identifier) is a 128-bit value, usually written as 32 hex characters in five dashed groups (like f47ac10b-58cc-4372-a567-0e02b2c3d479), designed to be unique across every system, every time, without a central authority coordinating who gets which ID. That's what makes it the standard choice for database primary keys, API request IDs, and distributed-system record identifiers.
SmartGen generates version 4 (random) UUIDs using crypto.randomUUID() — the browser's built-in cryptographically secure UUID generator — entirely client-side.
Why Use This Online UUID Generator
🎲 True UUID v4
Generated with the browser's native crypto.randomUUID() — spec-compliant, cryptographically random.
⚡ Generate in One Click
No signup, no rate limit — generate one UUID or a batch, instantly.
🔒 Nothing Logged
Generation happens locally — SmartGen never sees or stores the IDs you generate.
How to Generate a UUID Online
- Click Generate to produce a new random UUID v4.
- Copy it using the Copy button — it's ready to paste directly into a database seed script, a config file, or test data.
- Generate again for each additional unique ID you need — every click produces an independent value.
Where UUIDs Are Actually Used
UUIDs solve a specific problem: uniqueness without coordination. Common places you'll run into them:
1. Database primary keys
Unlike auto-incrementing integers, UUIDs can be generated on the client or across multiple database shards without any risk of two records colliding on the same ID.
2. API request and trace IDs
Attaching a UUID to each API request makes it possible to trace that exact request through logs across multiple services, without ambiguity.
3. Session and idempotency keys
A UUID generated client-side and sent with a request (e.g. a payment) lets a server safely detect and reject an accidental duplicate submission.
Frequently Asked Questions (FAQ)
Q: What's the chance of two UUIDs colliding?
A: For UUID v4, effectively zero in practice — with 122 random bits, you'd need to generate roughly a billion UUIDs per second for about 85 years before a 50% chance of a single collision.
Q: Is this a UUID v4, and what does that mean?
A: Yes. "v4" means the UUID is generated from random (or pseudo-random) bits, as opposed to v1 (timestamp + hardware address based) or v5 (name-based hashing). v4 is the most common choice for general-purpose unique IDs.
Q: Does SmartGen store the UUIDs I generate?
A: No — each UUID is generated locally in your browser via crypto.randomUUID() and never transmitted anywhere.