UUID Generator

What is UUID Generator?

A UUID generator creates Universally Unique Identifiers — 128-bit values designed to be unique across space and time without central coordination. UUIDs serve as primary keys in databases, correlation IDs in distributed tracing, session identifiers, file names, and test data fixtures across virtually every modern technology stack.

UUID version 4 (random) is the most widely used variant, generating identifiers from cryptographically secure random numbers. The standard format displays 32 hexadecimal digits in five groups separated by hyphens: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where the version and variant bits are set according to RFC 4122.

Manually inventing unique IDs is error-prone — collisions, predictable patterns, and formatting mistakes cause data integrity issues. A proper generator uses the Web Crypto API's crypto.randomUUID() or equivalent secure random sources to produce IDs that are statistically unique for all practical purposes.

Our generator runs entirely in your browser with no server involvement. Generated UUIDs are created locally and never logged, stored, or transmitted. This matters when generating IDs for security-sensitive contexts like session tokens, API keys, or file encryption identifiers.

Use generated UUIDs with the JSON Formatter when embedding them in API payloads, the JWT Decoder when the jti (JWT ID) claim needs inspection, or Base64 Encode when UUIDs must travel in encoded transport formats.

When should you use UUID Generator?

Generate primary keys for database tables when using UUID columns instead of auto-increment integers. UUIDs enable distributed ID generation without coordination and safe data merging across shards and replicas.

Create correlation IDs for distributed tracing and request logging. Assign a unique UUID to each incoming HTTP request and propagate it through microservices so log aggregation tools can reconstruct the full request path.

Produce test data fixtures for unit tests, integration tests, and seed scripts. Bulk-generate dozens of UUIDs at once for populating test databases with realistic primary key values.

Name temporary files, upload directories, and cache keys in applications where collision-free unique names are required without a central naming authority.

How to Use UUID Generator

1. Set the number of UUIDs to generate (1-100).
2. Click Generate to create UUIDs.
3. Copy individual UUIDs or all at once.
4. Use generated UUIDs in your database, API, or tests.

Features

• Generate UUID v4 with cryptographically secure randomness
• Bulk generate up to 100 UUIDs in a single click
• Copy individual UUIDs or all generated values at once
• Standard RFC 4122 format with correct version and variant bits
• Instant generation — no server round-trips required
• Privacy-first — generated IDs never leave your browser
• One-click regenerate for fresh batches of unique IDs
• Perfect for database keys, APIs, tracing, and testing

Example

Each generated UUID follows the RFC 4122 format with 32 hex digits in five hyphenated groups. The third group starts with 4, indicating version 4 (random). The fourth group's first character (a, b, 8, or 9 in this example) encodes the variant. Every click produces a statistically unique value suitable for use as a database primary key, session ID, or correlation identifier.

Click Generate (1 UUID)

550e8400-e29b-41d4-a716-446655440000

Common Errors

Best Practices

• Use cryptographically secure generators for all production identifiers
• Store UUIDs in native UUID column types when your database supports them
• Normalize to lowercase for consistent string comparisons and indexing
• Generate locally — no need to call external APIs for UUID creation
• Use bulk generation for test fixtures rather than hardcoding predictable values
• Document UUID version choice (v4 vs v7) in your architecture decision records
• Include UUIDs in JSON API responses formatted with the JSON formatter for readability
• Propagate correlation UUIDs through all microservice logs for distributed debugging

Frequently Asked Questions