Generate Cryptographically Secure UUID v4 & GUIDs
Produce RFC 4122 compliant version 4 UUIDs for database primary keys, API tokens, and distributed systems. Generate single or bulk identifiers with complete privacy.
How to Generate UUIDs
Produce RFC 4122 compliant version 4 UUIDs for database primary keys, API tokens, and distributed systems. Generate single or bulk identifiers with complete privacy.
Select Quantity
Choose how many UUIDs you need to generate (from 1 up to 500 identifiers in a single click).
Configure Format
Toggle hyphens, uppercase/lowercase formatting, and optional curly brace enclosure.
Execute Generation
Our browser-native crypto engine generates random UUIDs conforming to standard RFC 4122 v4 specs.
Copy or Download
Copy generated UUIDs to your clipboard or download them as a clean text file for development.
Why Generate UUIDs with Khalasna?
RFC 4122 Compliance
Strict version 4 variant-1 implementation with proper version (0100) and variant (10xx) bit masking.
Hardware CSPRNG Randomness
Employs crypto.randomUUID() and crypto.getRandomValues() for zero collision probability.
Bulk Output Formats
Generate hundreds of UUIDs formatted as plain text, JSON arrays, or comma-separated lists.
100% Private Client-Side Logic
All identifiers are generated locally in your browser memory without server logging.
Technical Overview: RFC 4122 v4 Bitmasking & Collision Probability
A Version-4 UUID (Universally Unique Identifier) is a 128-bit label formatted as 32 hexadecimal digits displayed in five groups separated by hyphens (8-4-4-4-12): xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. Khalasna generates UUIDs using the browser's native crypto.randomUUID() or cryptographic random byte arrays. To ensure strict compliance with RFC 4122, 122 bits are populated with true cryptographic randomness, while 6 bits are multiplexed with specific constants: bits 48-51 are masked with 0x4 to set version 4, and bits 64-65 are masked with 0x8, 0x9, 0xa, or 0xb to establish the DCE 1.1 variant. The probability of generating a duplicate UUID v4 is approximately 1 in 2^122 (or 5.3 * 10^36)—requiring generating 1 billion UUIDs every second for 85 years to experience a 50% chance of a single collision. All generation runs locally in memory.
Common Applications for UUID Generation
Database Primary Keys
Generate globally unique record identifiers for distributed databases like PostgreSQL, MongoDB, and CockroachDB.
API Request Tracing
Create unique transaction IDs and correlation tokens for microservice telemetry and logging.
Software Testing & Mock Data
Populate test fixtures and mock API endpoints with realistic, valid UUIDv4 strings.
Frequently Asked Questions
What is the difference between a UUID and a GUID?
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What is the difference between a UUID and a GUID?
+GUID (Globally Unique Identifier) is Microsoft's implementation of the standard UUID. A UUID v4 is structurally identical to a GUID.
Can two generated UUIDs ever collide?
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Can two generated UUIDs ever collide?
+The collision probability is so infinitesimally small (1 in 5.3 x 10^36) that it is virtually impossible in practical computing.
Are generated UUIDs sent to or saved on your servers?
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Are generated UUIDs sent to or saved on your servers?
+No. All UUIDs are generated 100% locally in your web browser. Nothing is ever sent to or stored on our servers.
Can I generate UUIDs without hyphens?
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Can I generate UUIDs without hyphens?
+Yes, you can toggle hyphens off to get a clean 32-character continuous hexadecimal string.
Is this UUID generator free for commercial software?
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Is this UUID generator free for commercial software?
+Yes, it is completely free with no usage limits or licensing restrictions.