UUID ULID Generator Tool - Generate and Decode UUID v4, v7 and ULID

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This tool generates universally unique identifiers in three formats: UUID v4 (random), UUID v7 (time-ordered), and ULID (lexicographically sortable). You can also decode existing UUIDs and ULIDs to inspect their version, variant, and embedded timestamps.

All processing is performed entirely in your browser using the Web Crypto API. No data is transmitted to any server. Your generated IDs never leave your device.

  • This tool is provided "AS IS" without any warranties of any kind.
  • The author accepts no responsibility for collisions, misuse, or any issues arising from the use of generated IDs.
  • Generated IDs use cryptographically secure random number generation (Web Crypto API).
  • By using this tool, you accept full responsibility for any outcomes.

This tool uses client-side JavaScript for all processing. No data is transmitted to servers, no files are uploaded online, all processing happens locally in your browser. Once loaded, this tool continues to work even without an internet connection. For more details, please refer to our Web Tools Disclaimer.

Options:

Decode / Inspect UUID or ULID


Features:

  • UUID v4 Generation: Cryptographically secure random UUIDs using crypto.randomUUID() with fallback
  • UUID v7 Generation: Time-ordered UUIDs with 48-bit millisecond timestamp (RFC 9562)
  • ULID Generation: Lexicographically sortable identifiers using Crockford's Base32 encoding
  • Batch Generation: Generate up to 1000 IDs at once
  • Decode / Inspect: Extract version, variant, and embedded timestamps from existing UUIDs and ULIDs
  • Client-Side Only: All generation uses the Web Crypto API - no data ever leaves your browser
  • Uppercase Option: Toggle between lowercase and uppercase output
  • One-Click Copy: Copy all generated IDs to clipboard instantly

Common Use Cases:

  • Database Primary Keys: Generate unique IDs for database records (UUID v7 recommended for B-tree performance)
  • API Development: Create request IDs, correlation IDs, and idempotency keys
  • Distributed Systems: Ensure globally unique identifiers without coordination
  • Testing & Development: Quickly generate test data with realistic unique IDs
  • Log Correlation: Use time-sortable IDs (UUID v7 / ULID) to trace events across services

References:
Tech Blog with curated related content
Web Tools Collection

Written by Hidekazu Konishi