UUID Generator

Generate cryptographically strong UUID v4 values in bulk, with hyphen and case options.

Generated (0)

Click "Generate New UUIDs" to create some.

What Is a UUID, and Why Is the v4 Identifier the Standard?

A Universally Unique Identifier (UUID) is a 128-bit number used to identify information in computer systems. It's also referred to as a GUID within the Microsoft ecosystem. The biggest advantage of a UUID is that it can generate statistically unique values without any central registration authority. The probability of two UUIDs colliding mathematically converges to zero, guaranteeing near-perfect uniqueness for virtually every real-world use case.

While several versions of UUID exist, v4 is the version modern developers prefer most. Unlike the time-based v1 or namespace-based v3/v5, a UUID v4 is generated using cryptographically strong random numbers. Because it's impossible to infer the generating device's information or the time it was created, it offers excellent security and privacy benefits. DevTora's UUID Generator delivers an ultra-fast workflow that instantly creates up to 100 RFC 4122-standard v4 identifiers with a single click. Use it with confidence whenever you need unique IDs — for initial database seeding, generating primary keys for a microservice, or labeling session tokens.

How to Generate Bulk UUIDs with Custom Settings

  1. 1

    Set the generation count: Choose how many unique IDs you need, from 1 up to a maximum of 100.

  2. 2

    Adjust the hyphen option: The default is the standard format (8-4-4-4-12). Turn the option off if you need a clean string with no separators.

  3. 3

    Specify letter casing: Freely choose lowercase or uppercase output to match your project's conventions.

  4. 4

    Run the generation: Click "Generate New UUID" and the secure random number engine instantly fills the results list.

  5. 5

    Audit the results: Scroll through the list of uniquely generated identifiers in the results panel to review them.

  6. 6

    Copy in bulk: Use the "Copy All" button to grab every generated UUID onto your clipboard for immediate use.

  7. 7

    Clean up your workspace: Use the "Clear Results" button to reset the list and prepare for a new batch.

  8. 8

    Verified uniqueness: A brand-new, cryptographically secure set of random numbers is generated for every single request.

  9. 9

    Local privacy: All random computation runs entirely inside your browser, and no data is ever sent to a server.

  10. 10

    Code and DB integration: Paste the generated strings directly into a SQL script, a JSON config file, or your source code.

An Enterprise-Grade UUID Toolkit for Scalable Systems

  • Full RFC 4122 standard compliance: Generates valid v4 UUIDs recognized by every modern system.
  • Bulk generation support: Produces up to 100 unique identifiers in a single high-performance operation.
  • Custom formatting options: Easily toggle hyphens and letter casing on or off.
  • Cryptographically secure-grade logic: Uses the Web Crypto API to guarantee high-entropy random numbers.
  • Instant local operation: Delivers millisecond-level responsiveness with zero server communication.
  • A polished, refined UI: An interface designed to boost readability and focus during development.
  • 100% privacy protection: Generated identifiers are never logged or stored, fully protecting your data sovereignty.
  • One-click clipboard integration: A copy workflow optimized to make handling large batches of IDs convenient.
  • A fully responsive web interface: Generate IDs quickly from a mobile device even while you're on the move.
  • Zero-dependency engine: Runs independently in every modern web browser with no additional libraries to install.
  • A dynamic counter system: Check and manage how many IDs have been generated in real time.
  • Full dark mode support: Delivers an optimal visual experience matched to your system theme.

Common Mistakes to Avoid When Implementing UUIDs

Generating Predictable Random Numbers

A UUID based on Math.random() is insecure. DevTora guarantees safety by using the crypto API instead.

Confusion Over Version Choice

Using v1 (time-based) in a distributed system can cause collisions due to synchronization issues. An independent v4 is recommended instead.

Incorrect String Length

A UUID must consist of exactly 32 hexadecimal characters. Being off by even a single character will break a database's constraints.

Mistaking It for a Security Key

Just because a UUID v4 is random doesn't mean it should be treated as an all-purpose "secret key" on its own, without additional security measures.

Excessive Fear of Collisions

The probability of a v4 UUID collision is 1 in 2^128. You'd need to generate billions per second, continuously, for centuries before one would ever occur.

Inefficient Storage

A binary (16-byte) format is faster than storing a UUID as a 36-character string. Take advantage of your database's dedicated UUID type.

The Universally Unique Identifier Master Guide FAQ

  1. 1

    Is it possible for UUIDs to collide?

    Mathematically possible, but practically almost impossible. The number of possible v4 UUIDs vastly exceeds the number of grains of sand on Earth.

  2. 2

    What's the difference between a UUID and a GUID?

    They're effectively the same thing. GUID is the term primarily used by Microsoft, while UUID is the RFC 4122 standard term.

  3. 3

    Is a generated v4 UUID really random?

    Yes. It's designed to be unpredictable using your browser's cryptographically secure pseudo-random number generator (CSPRNG).

  4. 4

    Why do hyphens appear in the output?

    The 8-4-4-4-12 format is the standard readable format defined in the RFC 4122 specification, improving readability.

  5. 5

    Is it okay to use a UUID as a primary key in a SQL database?

    Yes. It's a far more efficient and secure approach than an auto-incrementing integer in a distributed server environment.

  6. 6

    Can a UUID reveal where it was generated?

    Not with version 4. Version 1 used to embed a MAC address, but v4 consists entirely of completely random data.

  7. 7

    Does using this tool cost anything?

    No. DevTora is a free developer utility that anyone can use with no usage limits.

  8. 8

    Does UUID v4 follow any specific positional rules?

    The first character of the third group is always "4," which indicates that the UUID is version 4.

  9. 9

    Is uppercase or lowercase the standard?

    Lowercase is generally the standard, but many systems are case-insensitive. Choose based on your project's conventions.

  10. 10

    How many can I generate at once?

    For browser performance and clear reviewability, generation is limited to a maximum of 100 at a time.

  11. 11

    Does this work in an offline environment?

    Yes — once the page has loaded, all generation logic runs entirely on your device, so it works without an internet connection.

  12. 12

    What's better about this than the terminal's uuidgen?

    It's convenient thanks to the visual interface, bulk generation, and graphical controls for toggling case and hyphens.

  13. 13

    Is it okay to use a UUID as a file name?

    It's highly recommended! It prevents filename collisions and obfuscates file names for security during uploads.

  14. 14

    How many characters long is a UUID in total?

    It's 32 characters excluding separators, or 36 characters total when including the 4 hyphens.

  15. 15

    Is generated UUID data stored on a server?

    Never. All information lives only in your browser's memory and disappears the moment you close the page.

  16. 16

    What does the first character of the fourth group mean?

    It indicates the RFC 4122 standard variant, and is typically expected to start with one of 8, 9, a, or b.