Online UUID Generator Tool

• Hash Generator
• Base64 Encoder/Decoder
• All converters

UUIDs give you identifiers that are extremely unlikely to collide across systems, which simplifies primary keys in distributed databases, resource IDs in APIs, session tokens, and file naming without a central allocator.

Benefits of UUIDs

• Uniqueness: Extremely low collision probability when generated correctly, so independent services can mint IDs safely.
• Distributed systems: Clients or services can create IDs without calling a central sequence.
• Database keys: Popular as surrogate primary keys when natural keys are awkward or merge-friendly schemas matter.
• Harder to guess: Random v4 values do not expose sequential counters, which helps against trivial enumeration (still not a substitute for proper auth).
• Standards-based: RFC 4122 defines formats and version bits so tools and languages interoperate.

This tool focuses on the two versions developers use most often. Pick the one that matches your ordering, privacy, and compatibility requirements.

Versions available here

• UUID v4 (random): Uses random or pseudo-random data for the payload bits; recommended default for new designs.
• UUID v1 (time-based): Incorporates a timestamp; useful when monotonic or sortable-by-time behavior helps, with different leakage characteristics than pure random IDs.

A few details prevent surprises when you store, index, or compare UUID strings.

Quick reference

• A UUID is 128 bits and is often shown as 32 hex digits in the 8-4-4-4-12 pattern with hyphens.
• UUID v4 exposes 122 bits of randomness in the payload (version and variant bits are fixed).
• String UUIDs are wider than integer keys; index and storage design should account for length.
• Lowercase versus uppercase hex is a presentation choice; comparisons are usually case-insensitive.
• RFC 4122 also defines other versions (for example v3, v5); this page generates v1 and v4 only.

Best practices

Use the right version for your threat model and storage layer, and treat UUIDs as identifiers—not secrets by themselves.

• Prefer UUID v4 for general-purpose unique IDs unless you have a clear reason to use v1.
• Store UUIDs consistently (string vs binary) and index according to your database’s recommendations.
• Do not rely on UUID randomness alone to secure sensitive resources; always enforce authorization.
• For very high insert rates, benchmark how UUID string keys affect B-tree fragmentation versus sequential IDs.
• When exposing IDs in URLs, combine unpredictability with access control appropriate to the data.

Typical use cases

• Database primary keys: Surrogate keys that merge cleanly across shards or offline clients.
• API resources: Stable, opaque identifiers in JSON responses and hypermedia links.
• Session and correlation IDs: Track requests or browser sessions without a shared counter.
• Distributed workers: Workers generate job or file IDs without contacting a coordinator.
• Unique file names: Avoid collisions when uploading or caching user content.