KitVela

UUID Generator (Bulk Cryptographic v4 GUIDs)

Generate random UUIDs (v4) in bulk with custom formatting.

Generate cryptographically secure Version 4 UUIDs (Universally Unique Identifiers) in bulk directly in your browser. Choose quantity and formatting options including standard lowercase, uppercase, and hyphenless formats.
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How It Works & Calculation Method

A Universally Unique Identifier (UUID), also known in Microsoft ecosystems as a Globally Unique Identifier (GUID), is a 128-bit numerical label used to uniquely identify database records, user sessions, and software components.

Our generator utilizes the browser's cryptographically secure Web Crypto API (`crypto.randomUUID()`), guaranteeing true cryptographic randomness with near-zero probability of collision across distributed database systems.

The tool calls the browser's hardware-backed cryptographic random number generator to create 128 random bits.

Bits are mapped to the standard canonical 36-character hexadecimal format (8-4-4-4-12) with version 4 and variant bits explicitly preserved.

Mathematical Formula

Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx (where x is any hex digit, y is 8, 9, a, or b)

Worked Example: Canonical v4 UUID Breakdown

Generating a standard primary key for a distributed PostgreSQL database table.

•Call crypto.randomUUID() in browser sandbox.
•Generate 16 random octets.
•Set bit 12-15 of time-high field to 0100 (version 4).
•Set bit 6-7 of clock-seq-high field to 10 (variant 1).
•Sample output: 123e4567-e89b-42d3-a456-426614174000.
Final Result: Generated 36-character canonical v4 UUID

Common Pitfalls to Avoid

  • •Using Math.random() in code to create UUIDs (it lacks cryptographic entropy and risks duplicate collisions).
  • •Treating UUIDs as sequential keys (random v4 UUIDs cause index fragmentation in B-tree databases if unindexed).
  • •Confusing v4 random UUIDs with v1 time-based or v5 namespace-hashed UUIDs.

Who This Tool Is For

  • •Backend software engineers creating unique database primary keys and migration seeds.
  • •QA automation engineers generating mock test fixture records.
  • •API developers assigning unique trace correlation request IDs.

How to Use the UUID Generator

1

Select Quantity

Choose how many UUIDs you need (1 to 500).

2

Choose Format

Select standard lowercase, uppercase, or dash-free.

3

Copy All

Click generate and copy the formatted list to your clipboard.

Frequently Asked Questions

What is the probability of a UUID v4 collision?
The collision probability is virtually zero: you would need to generate approximately 2.71 quintillion UUIDs to have a 50% chance of a single duplicate.
What is the difference between UUID and GUID?
UUID and GUID are essentially synonymous; Microsoft typically uses GUID while the broader open-source community refers to UUID.
Does this tool use cryptographically secure randomness?
Yes, it leverages the browser's native window.crypto.randomUUID() API for hardware-level pseudo-random entropy.
Can I generate UUIDs without hyphens?
Yes, select the 'No Dashes' formatting option to receive compact 32-character hexadecimal strings.
Can I generate bulk UUIDs at once?
Yes, you can generate up to 500 UUIDs in a single click and copy them all simultaneously.
Are generated UUIDs stored on a server?
Never. All identifiers are generated locally in your browser memory and cease to exist once you close the page.

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Last updated: 10/9/2026