Multi-Version UUID Generator 🧬

Generate unique identifiers across all major versions (V1, V3, V4, V5)

1. Select UUID Version

2. Generated Single UUID

4. Generate Batch

📚 UUID Explained: Generation, Structure, and Use Cases

Core Concepts of Universally Unique Identifiers

A UUID (or GUID) is a 128-bit identifier used to uniquely label information. Its strength lies in decentralized generation, ensuring unique IDs across all systems without coordination.

128-bit Identifier (Structure)

A standard UUID uses 32 hex digits arranged in 5 groups (8-4-4-4-12) separated by hyphens, totaling 36 characters.

Use Case: Human-readable format for logs, URLs, and general data storage.

Version 4 (Random) (V4)

Generated purely from random numbers. High entropy and no external data.

Use Case: Primary keys, session tokens, and unique IDs where creation time is not important.

UUID Versions and Advanced Use Cases

While V4 is dominant, other versions exist for sorting, time-stamping, or derived naming.

Version 1 (Time-Based) (V1)

Generated using the current timestamp and MAC address. Chronologically sortable.

Use Case: Legacy systems needing IDs ordered by creation time.

V6/V7 (Time-Sortable) (V6/V7)

Modern time-based alternatives. V7 is the simplest and best choice for sortable primary keys.

Use Case: Optimal for databases requiring global uniqueness and sequential indexing.

V3/V5 (Name-Based) (V3/V5)

Generated by hashing a name (URL/email) with MD5 (V3) or SHA1 (V5).

Use Case: Ensures same input produces the same UUID.

Collision Safety (Probability)

Duplicate V4 UUID probability is extremely small, suitable for massive distributed systems.

Use Case: Useful in IoT or cloud services without centralized control.

Formatting Options and Tool Usage

UUIDs can be presented in multiple formats for different technical requirements.

  • Standard: Default format, easy to read and debug.
  • Compact/Uppercase: Saves space in database indexes and improves query speed.
  • URL-Safe Base64: Short 22-character string, safe for embedding in URLs.
  • Batch Generation: Quickly create multiple unique IDs for database seeding or provisioning.
V4 Structure Specifics

Most bits are random, but specific bits identify the version:

  • The Version is always 4 (first hex digit in third group).
  • The Variant starts with 10 binary (first hex digit in fourth group will be 8, 9, A, or B).

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