UUID/GUID Generator

What is a UUID?

A UUID (Universally Unique Identifier), often referred to as a GUID (Globally Unique Identifier), is a 128-bit number used to uniquely identify information in computer systems. The main purpose of a UUID is to guarantee uniqueness across all devices and all time, making it highly unlikely that the same identifier will ever be generated twice.

This makes UUIDs incredibly useful for:

• Database Primary Keys: Ensuring every record in a database has a unique ID, especially in distributed systems where auto-incrementing integers are not feasible.
• Transaction IDs: Uniquely identifying every transaction in a system.
• Object Identifiers: Assigning a unique ID to any object, file, or entity in software.
• Security Tokens: Generating unique tokens for sessions or API access.

Understanding UUID Versions

There are several versions of UUIDs, each generated differently:

• Version 1 (Timestamp-based): UUIDs are generated using a combination of the current timestamp and the MAC address of the computer generating it. This makes them predictable to a degree but guarantees uniqueness for a specific machine. They are useful when you need IDs that are time-sortable.
• Version 4 (Random): UUIDs are generated from purely random (or pseudo-random) numbers. This is the most common version used today, as it provides a high degree of randomness and uniqueness without revealing information about the time or machine it was created on.

This tool allows you to generate both Version 1 and Version 4 UUIDs.

Best Practices

• Prefer UUID v4 for most application identifiers; it avoids embedding timestamp/MAC information.
• Consider UUID v1 only when time‑ordering is important and privacy implications are acceptable.
• Do not expose UUIDs that could reveal internal record counts or timestamps unless necessary.
• Validate UUID format with a strict regex before accepting input from users.
• Treat UUIDs as opaque strings; do not parse or infer meaning from them.
• Use HTTPS and secure storage; UUIDs can still be sensitive when tied to user data.

Validation and format

A standard UUID is 36 characters: 32 hex digits and 4 dashes, like xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx where M is the version and N is the variant.

Example v4: xxxxxxxx-xxxx-4xxx-[8|9|a|b]xxx-xxxxxxxxxxxx

Common questions (FAQ)

1) Which version should I use?
Use v4 for random IDs in most systems. Use v1 if you need chronological ordering.

2) Are UUIDs guaranteed unique?
Mathematically, the collision probability for v4 is negligible for practical scales.

3) Are UUIDs secure?
UUIDs are identifiers, not secrets. Don’t rely on them as authentication tokens without additional security.

4) Can I shorten a UUID?
Base‑encoding is possible, but ensure reversibility/uniqueness and document the scheme.

5) How many can I generate at once?
The tool supports batch generation; copy a single value or copy all.

Related tools on ChangeBlogger

• Diff Checker – compare config changes where IDs are introduced.
• URL Parser – inspect query parameters that carry IDs.
• JWT Debugger – analyze tokens that may include UUID claims.

How to Use the UUID/GUID Generator

1. Select a Version: Choose between "Version 1 (Timestamp)" or "Version 4 (Random)" depending on your needs. For most modern applications, Version 4 is the recommended choice.
2. Set the Count: Specify how many UUIDs you want to generate at once.
3. Click "Generate": The tool will create the specified number of unique identifiers.
4. Copy Your UUIDs: You can copy an individual UUID by clicking the copy icon next to it, or copy all of them at once with the "Copy All" button.

Whether you're a developer needing unique IDs for a new application or just curious about how they work, this tool provides a fast and easy way to generate standard-compliant UUIDs.