🆔 UUID Tools

Complete UUID/GUID generation and validation toolkit supporting all RFC 4122 versions plus modern alternatives like ULID for distributed systems.

What are UUIDs?

UUID (Universally Unique Identifier) is a standardized identifier format designed to be globally unique across space and time. UUIDs are 128-bit values typically represented as 32 hexadecimal digits, displayed in five groups separated by hyphens: 123e4567-e89b-12d3-a456-426614174000.

UUIDs are defined by the RFC 9562 standard (which obsoletes the previous RFC 4122) and are used across computing platforms to identify information without requiring centralized registration or coordination.

UUID Format

All UUIDs share a common format consisting of 36 characters (32 hexadecimal digits plus 4 hyphens) arranged in the pattern:

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx

Where:

  • x is any hexadecimal digit (0-9, a-f)
  • M indicates the UUID version (1-7)
  • N indicates the UUID variant (typically 8, 9, A, or B for modern UUIDs)

Privacy & Processing

All UUID generation and validation happens locally in your browser using cryptographically secure random number generation. The tools never send your identifiers anywhere - everything processes on your device, making these utilities safe for handling sensitive system identifiers.

UUID v4 Generator

Generate cryptographically random UUID v4 identifiers perfect for database primary keys and session tokens without exposing system information.

UUID v1 Generator

Create timestamp-based UUID v1 identifiers that embed creation time and MAC address for distributed systems requiring traceability.

UUID v3 Generator

Generate deterministic UUID v3 identifiers using MD5 hashing of namespace and name for consistent IDs from same input.

UUID v5 Generator

Create secure name-based UUID v5 identifiers using SHA-1 hashing for better collision resistance than v3 from DNS names or URLs.

UUID v6 Generator

Generate modern UUID v6 identifiers that combine timestamp ordering with improved database indexing performance.

UUID v7 Generator

Create cutting-edge UUID v7 identifiers using Unix epoch timestamps with millisecond precision for modern distributed systems.

ULID Generator

Generate Universally Unique Lexicographically Sortable Identifiers with 26-character encoding for URL-safe, sortable alternatives to UUIDs.

Short UUID Generator

Create compact Short UUID identifiers using base62 encoding to reduce length from 36 to 22 characters for QR codes and URLs.

Nil UUID Generator

Generate the RFC 4122 Nil UUID (all zeros) representing empty or null UUID values for database initialization and default states.

UUID Decoder & Validator

Analyze and validate UUIDs of any version, extracting embedded information like timestamps, version numbers, and variant details for debugging.

Bulk UUID Generator

Generate thousands of UUIDs simultaneously for database seeding, load testing, and bulk data operations with export capabilities.

UUID Versions and Use Cases

These tools support all RFC standard UUID versions plus modern alternatives like ULID that address specific needs in distributed systems, databases, and URL-friendly applications. Whether you need random IDs, timestamp-based identifiers, or compact alternatives, the right UUID format ensures your system scales reliably.

Standard UUIDs: Create RFC compliant identifiers in versions 1, 3, 4, 5, 6, and 7 for different use cases.

Modern Alternatives: Generate ULIDs for lexicographically sortable IDs and Short UUIDs for compact applications.

Bulk Generation: Create thousands of UUIDs simultaneously for database seeding and load testing.

Analysis Tools: Decode existing UUIDs to extract embedded information and validate format compliance.

Comparison of UUID Versions

VersionNameGeneration MethodTime-orderedUse Cases
UUID v1TimestampCurrent timestamp + node ID (MAC)Yes (partially)Logging, distributed systems
UUID v3Name-based (MD5)MD5 hash of namespace + nameNoConsistent IDs for the same input
UUID v4RandomRandom or pseudo-random numbersNoGeneral purpose, most common
UUID v5Name-based (SHA-1)SHA-1 hash of namespace + nameNoConsistent IDs with stronger hash
UUID v6Reordered TimestampTimestamp (ordered for sorting)YesDatabase keys, time-sortable records
UUID v7Unix Epoch TimestampUnix timestamp + random dataYesModern sortable identifiers
Nil UUIDZero UUIDAll zerosN/ASpecial value, uninitialized marker

Advantages of UUIDs

  • No Coordination Required: Generate IDs without central coordination
  • Global Uniqueness: Extremely low collision probability
  • Fixed Length: Consistent 36 character string representation
  • Cross-Platform: Supported in virtually all programming languages
  • Versatile: Different versions for different use cases

Non-Standard UUID Alternatives

ID TypeDescriptionAdvantagesDisadvantages
GUIDMicrosoft's implementation of UUIDFunctionally equivalent to UUIDSome implementation differences in older systems
ULIDUniversally Unique Lexicographically Sortable IdentifierLexicographically sortable, timestamp first, case-insensitiveNewer, less widespread adoption
Snowflake IDTwitter's distributed ID systemTime-sortable, compact (64-bit)Requires central coordination
CUID/CUID2Collision-resistant IDsShort, suitable for client-side generationNot an official standard
Nano IDTiny, secure, URL-friendly unique string ID generatorSmaller than UUID, configurable alphabetNot standardized
Short UUIDShorter encoding of standard UUIDsMore compact representationRequires conversion to/from standard UUID
Nil UUIDUUID with all bits set to zeroSpecial semantic meaningNot unique (used as special value)
Minecraft UUIDUUIDs with or without hyphensCompatible with standard UUIDsFormatting differences only

Practical Applications

  • Database Primary Keys: Especially in distributed or replicated databases
  • Distributed Systems: Identify entities across multiple systems
  • Web Applications: Session identifiers, tracking anonymous users
  • Content Management: Document and media identifiers
  • APIs: Request and transaction identifiers for tracing and debugging
  • Internet of Things: Device identification without central registration
  • Data Synchronization: Identifying records across multiple data stores
  • Software Licensing: Unique product or license keys

Frequently Asked Questions

Is any data sent to your server?

No. All UUID generation and validation happens locally in your browser using JavaScript. Your identifiers and data never leave your device.

Which UUID version should I use?

UUID v4 for general use (random), v1 for timestamp-based with MAC address, v6/v7 for modern timestamp-based systems, v3/v5 for deterministic IDs from names, and ULID for sortable alternatives.

Are UUIDs truly unique?

Yes. When generated properly, UUIDs have such low collision probability that they're considered unique for practical purposes. Random UUIDs (v4) have 2^122 possible values.

What's the difference between UUID and ULID?

ULIDs are 26 characters (vs 36 for UUIDs), lexicographically sortable by creation time, URL-safe, and case-insensitive while maintaining the same uniqueness guarantees.

Can I use these for database primary keys?

Yes. UUID v4 is excellent for distributed databases, while v6/v7 provide timestamp ordering that improves database indexing performance. ULID offers similar benefits with shorter length.

Resources