UUID (Universally Unique Identifier) is a 128-bit identifier used to uniquely identify information. Format: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx (36 characters with hyphens). UUIDs are designed to be unique across all systems without central coordination.

When should I use UUIDs?

Use UUIDs for: database primary keys (distributed systems), session IDs, file names, API request IDs, user identifiers, and any case needing unique identifiers across systems. They eliminate the need for centralized ID generation.

UUID Generator - Generate Unique IDs

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What is UUID Generator?

A UUID (Universally Unique Identifier) is a 128-bit identifier used to uniquely identify information in distributed systems. UUIDs are designed to be unique across space and time, making them ideal for database primary keys, session identifiers, transaction IDs, and any scenario where unique identification is critical. The standard format is 8-4-4-4-12 hexadecimal digits (32 characters, 36 with hyphens).

How to Use

Set the number of UUIDs to generate (1-100).
Choose UUID version: v4 (random) or v1 (timestamp-based).
Click 'Generate' to create unique UUIDs.
Each UUID appears in a separate row with a copy button.
Click 'Copy All' to copy all UUIDs as a newline-separated list.
Use generated UUIDs in your database, API, or application.

Why Use This Tool?

Generate truly unique identifiers with virtually zero collision probability

UUID v4 uses random generation - no predictable pattern

UUID v1 includes timestamp - useful for chronological ordering

Batch generation saves time when you need multiple UUIDs

Copy single UUID or all UUIDs with one click

No server dependency - all generation happens in your browser

Tips & Best Practices

UUID v4 is recommended for most use cases - simpler and more random
UUID v1 can leak timing information - avoid for security-sensitive contexts
UUID collision probability is astronomically low but theoretically possible
Store UUIDs as strings in databases (36 chars) or convert to binary (16 bytes)
Use UUIDs for primary keys in distributed systems to avoid coordination
Consider ULID if you need sortable unique identifiers

Frequently Asked Questions

What's the difference between UUID v1 and v4?

UUID v1 is generated from the current timestamp and machine's MAC address, making it time-sortable but potentially revealing system information. UUID v4 is generated from random numbers, offering better privacy and unpredictability. For most applications, v4 is preferred unless chronological ordering is specifically required.

How unique are UUIDs?

UUIDs have 128 bits (2^128 possible values). For UUID v4, the collision probability is extremely low: generating 1 billion UUIDs per second for 85 years would have a 50% collision chance. In practical terms, UUID collisions are virtually impossible in normal applications.

Can I use UUIDs as database primary keys?

Yes, UUIDs are excellent primary keys for distributed systems where multiple nodes generate records independently. Unlike auto-increment IDs, UUIDs require no coordination. However, they're larger than integer IDs (36 characters vs 4-8 bytes), which can affect storage and indexing performance.

Why are UUIDs 36 characters long?

UUIDs contain 128 bits, which is 32 hexadecimal characters. The 36-character format adds 4 hyphens for readability in the pattern 8-4-4-4-12: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. Some systems store UUIDs without hyphens (32 chars) or as binary (16 bytes) to save space.

Are UUIDs secure?

UUID v4 is suitable for non-secret identification but not for security tokens or secrets - it's just random, not cryptographically strong. UUID v1 reveals timestamp and potentially MAC address. For security tokens, use cryptographic random generators or dedicated token formats like JWT.

What about ULID vs UUID?

ULID (Universally Unique Lexicographically Sortable Identifier) is a newer format that combines timestamp randomness with lexicographic sortability. Unlike UUID v1, ULID is sortable without revealing exact timing. If you need time-ordered unique IDs, ULID may be better than UUID v1.

UUID Generator