UUID Generator & Validator

Generate universally unique identifiers (UUIDs) in multiple versions and formats. Validate existing UUIDs and decode their information.

Options

Randomly generated (most common)

Generated UUIDs

No UUIDs generated yet. Click "Generate UUID" to create some!

Multiple Versions

Generate v1 (timestamp), v4 (random), and v5 (namespace) UUIDs

Bulk Generation

Create up to 100 UUIDs at once for your applications

Multiple Formats

Standard, uppercase, no hyphens, braces, or URN format

Validation

Validate and decode UUID version, variant, and structure

Common Use Cases

Database Records

Use UUIDs as primary keys in distributed databases to avoid collisions

API Development

Generate unique request IDs for tracking and debugging API calls

File Naming

Create unique filenames for uploads and temporary files

Session Management

Generate secure session tokens and authentication identifiers

Frequently Asked Questions

What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit number used to identify information in computer systems. The probability of generating duplicate UUIDs is so low that they can be considered unique for practical purposes.
Which UUID version should I use?
  • Version 4 (Random): Most common, good for general use
  • Version 1 (Timestamp): When you need time-based ordering
  • Version 5 (SHA-1): When you need deterministic UUIDs from a namespace and name
Are UUIDs really unique?
While not mathematically guaranteed to be unique, the probability of generating duplicate UUIDs is extremely small. For UUID v4, you'd need to generate about 2.71 quintillion UUIDs before having a 50% chance of collision.
Can I extract information from a UUID?
Yes, for some versions. Version 1 UUIDs contain timestamp and MAC address information. Version 3 and 5 UUIDs are derived from namespace and name. Version 4 UUIDs are random and contain no extractable information beyond the version and variant.

Free UUID / GUID Generator Online

A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit label used to uniquely identify objects in software systems. Our free UUID generator creates UUIDs in versions 1, 4, and 5 — the most commonly used formats in databases, APIs, distributed systems, and microservices.

You can generate a single UUID or bulk-generate hundreds at once. All generation happens instantly in your browser — no server calls, no data collection, no rate limits. Validate existing UUIDs to check their format and version, and export your results in multiple formats.

How to Generate UUIDs

  1. 1

    Select UUID version

    Choose v4 (random) for most use cases, v1 (time-based) for ordered IDs, or v5 (namespace + name hash) for deterministic UUIDs.

  2. 2

    Set quantity

    Enter how many UUIDs you need — from 1 to thousands. Bulk generation is instant.

  3. 3

    Choose format

    Select standard format (with hyphens), no-hyphens, uppercase, or braces notation depending on your system's requirements.

  4. 4

    Generate and copy

    Click Generate and copy individual UUIDs or the entire list to your clipboard for pasting into your code, database, or spreadsheet.

  5. 5

    Validate an existing UUID

    Paste any UUID string into the validator to confirm it is well-formed and identify its version.

Common Use Cases for UUIDs

Database Primary Keys

Use UUID v4 as primary keys instead of auto-incrementing integers. UUIDs work across distributed databases and prevent ID enumeration attacks.

API Resource Identifiers

Assign UUIDs to API resources (users, orders, sessions) so client-facing IDs are random and unpredictable.

Session Tokens

Generate UUIDs as session IDs or CSRF tokens for web applications requiring unique, hard-to-guess identifiers.

File Naming

Rename uploaded files with UUID names to avoid collisions and prevent overwriting when storing in object storage (S3, GCS, etc.).

Microservices Correlation IDs

Assign a UUID to each request to trace it across distributed services and correlate logs from multiple systems.

Testing & Seeding

Bulk-generate UUIDs to seed databases, create test fixtures, or populate mock data for QA environments.

Frequently Asked Questions

What is the difference between UUID v1, v4, and v5?
UUID v1 is time-based and includes the host MAC address, making it sortable but potentially revealing. UUID v4 is completely random and is the most widely used version. UUID v5 is deterministic — the same namespace and name always produce the same UUID, useful for reproducible IDs.
Can two UUIDs ever be the same?
Theoretically yes, but the probability is astronomically small. With v4 UUIDs, there are 2^122 possible values. You would need to generate billions of UUIDs per second for trillions of years before a collision becomes likely.
What is the difference between UUID and GUID?
They are the same thing. GUID (Globally Unique Identifier) is Microsoft's term for UUID. Both follow the same RFC 4122 standard and have identical format and behavior.
Should I use UUID or auto-increment integers as database primary keys?
Both work, but UUID v4 offers advantages: they are globally unique (safe for distributed systems), don't expose record counts, and can be generated client-side. The trade-off is slightly larger storage size (16 bytes vs 4-8 bytes for integers).
Are the UUIDs generated here truly random?
Yes. We use the Web Crypto API (crypto.randomUUID or crypto.getRandomValues) which provides cryptographically secure randomness — the same standard used in security-critical applications.

UUID Format and Structure

A UUID is represented as 32 hexadecimal digits grouped as 8-4-4-4-12 and separated by hyphens:550e8400-e29b-41d4-a716-446655440000. The version number appears as the first digit of the third group. The variant indicator occupies the first 1-3 bits of the fourth group.

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