Random UUID Generator

What is a UUID (Universally Unique Identifier)?

A UUID (Universally Unique Identifier) is a 128-bit (16-byte) identifier standardized by RFC 4122 and updated by RFC 9562 in 2024. UUIDs provide statistical uniqueness across distributed computing environments without relying on a central database coordinator or auto-incrementing serial sequences.

In canonical text form, a UUID is represented as a 36-character hexadecimal string: xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx where M indicates the version and N indicates the variant.

Understanding UUID Versions: v4 vs v7 vs v1

UUID Version 4 (Pure Random)

UUID v4 is the most widely used format. It uses 122 bits of cryptographically secure random data generated via the browser's native crypto.randomUUID() API. The collision probability is approximately 1 in 5.3 x 10³⁶ unique identifiers.

• Collision Probability: Generating 1 billion UUIDs per second for 85 years yields a 50% chance of one collision.
• Use Cases: Session tokens, API keys, file upload identifiers, transient request tracking.

UUID Version 7 (Time-Ordered Modern Standard - RFC 9562)

UUID v7 embeds a 48-bit Unix epoch millisecond timestamp into the most significant bits (MSB), followed by 62 random bits. This makes UUID v7 values chronologically sortable, ideal for database primary keys.

• Database B-Tree Locality: UUID v7 values increase monotonically with time, preventing expensive random disk I/O page splits in PostgreSQL, MySQL (InnoDB), and SQLite B-tree indexes.
• Use Cases: Primary key columns, distributed event logs, transactional order IDs.

UUID Version 1 (Timestamp + Node)

UUID v1 uses a 60-bit timestamp measured in 100-nanosecond intervals since October 15, 1582 (Gregorian epoch), combined with a clock sequence and a 48-bit node identifier. While it provides temporal ordering, the timestamp is split across non-contiguous bit positions, making it less suitable for database indexing than UUID v7.

Minecraft Player UUIDs (Offline Mode MD5)

Minecraft offline mode servers generate player UUIDs using an MD5 hash of "OfflinePlayer:" + username formatted as a Version 3 UUID. Our tool implements this exact algorithm for server administrators, modders, and plugin developers.

UUID vs GUID: Is There Any Difference?

GUID (Globally Unique Identifier) is Microsoft's implementation of the UUID standard. Every valid GUID is a UUID. GUIDs are conventionally displayed in uppercase with curly braces: {C02A8400-E29B-41D4-A716-446655440000}.

Comparison Matrix of Identifier Formats

Format	Length	Sortable?	Basis	Best Use
UUID v4	36 chars	No	122-bit Random	API Keys, Tokens
UUID v7	36 chars	Yes	Time + Random	Database PKs
ULID	26 chars	Yes	Crockford Base32	Short Sortable IDs
NanoID	21 chars	No	URL-Safe Random	Short Public URLs

Frequently Asked Questions

What is a UUID and why do I need one?

A UUID is a 128-bit identifier standardized by RFC 4122 and RFC 9562. It guarantees statistical uniqueness across distributed systems without a central coordinator.

Are UUIDs truly unique?

UUID v4 has 2^122 possible values. You would need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of a single collision.

Which UUID version should I use for database primary keys?

UUID v7 (RFC 9562) is optimal for database primary keys because its time-ordered nature maintains B-tree index locality, preventing random page splits.

What is the difference between UUID and GUID?

GUID is Microsoft's name for UUID. Every valid GUID is a UUID. GUIDs are typically shown uppercase in curly braces in .NET/C# ecosystems.

How do I generate a UUID in JavaScript?

Use the native Web Crypto API: const uuid = crypto.randomUUID(); This works in all modern browsers, Node.js 19+, Deno, and Bun.

Is this tool safe to use? Is my data private?

Yes. All UUIDs are generated entirely in your browser using the Web Crypto API. No data is ever sent to any server. Your generated UUIDs never leave your device.

How does the Minecraft UUID Generator work?

Minecraft offline mode computes an MD5 hash of "OfflinePlayer:username" and formats it as a Version 3 UUID. Our tool implements this exact algorithm client-side.

Can I generate UUIDs in bulk?

Yes. Select any quantity from 1 to 1,000 from the Quantity dropdown. Bulk UUIDs can be exported as plain text, CSV, JSON array, or SQL INSERT statements.