ULID Generator

ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit identifier that combines a 48-bit timestamp with 80 bits of randomness. Unlike traditional UUIDs, ULIDs are lexicographically sortable, meaning they can be ordered alphabetically while preserving chronological order. This makes them ideal for distributed systems, event logs, and database records where both uniqueness and time-based sorting are essential.

Key Features of ULID:

• 128-bit Format: Compatible with UUID storage and systems.
• Timestamp Prefix: 48-bit Unix timestamp with millisecond precision for sortability.
• Random Component: 80 bits of cryptographic randomness for uniqueness.
• Lexicographic Sorting: Can be sorted as strings while maintaining time order.
• Base32 Encoding: Uses Crockford's Base32 (case-insensitive, no ambiguous characters).
• URL Safe: No special characters—ideal for URLs, file names, and APIs.

Common Use Cases

• Database Primary Keys: Combines benefits of auto-increment (sortability) with UUID (distributed uniqueness).
• Event Sourcing: Natural ordering for event streams and audit logs.
• Distributed Logs: Sort log entries across multiple services without centralized coordination.
• Time-Series Data: Perfect for IoT data, analytics, and monitoring systems.
• API Request IDs: Traceable, sortable identifiers for request/response tracking.

Best Practices for ULID

• ✅ Use for ordered data: Ideal when chronological sorting is important.
• ✅ Store as strings or binary: Works well in both formats depending on your database.
• ✅ Ensure time synchronization: Accurate timestamps across distributed systems prevent ordering issues.
• ✅ Handle millisecond collisions: Multiple ULIDs in the same millisecond are still unique due to randomness.
• ✅ Leverage Base32 encoding: Human-readable and copy-paste friendly compared to hexadecimal UUIDs.

Advantages of ULID

• 📅 Time-Ordered: Natural sorting by creation time without additional fields.
• 🌍 Globally Unique: Works seamlessly across distributed systems.
• 🔤 Case Insensitive: Easier to read and type compared to mixed-case UUIDs.
• 🔗 URL Safe: No encoding needed for web APIs and file paths.
• ⚡ Efficient Indexing: Sequential nature improves database index performance.
• 📦 Compact: 26 characters vs. 36 for standard UUID representation.

Potential Drawbacks

• ⏱️ Timestamp Exposure: Creation time is embedded—may reveal information about system activity.
• 🕐 Clock Dependency: Requires accurate system clocks; clock skew can affect ordering.
• 📚 Less Universal: Not as widely supported as standard UUIDs in legacy systems.
• 💾 Storage: Still 128 bits, larger than auto-incrementing integers.

Why Choose ULID?

ULID is perfect for modern distributed applications that need both global uniqueness and chronological ordering. It's an excellent alternative to UUIDv4 when you want the benefits of auto-incrementing IDs without centralized coordination.

If you're working with event-driven architectures, microservices, or time-series databases, ULID provides the best of both worlds—randomness for uniqueness and timestamps for natural sorting.

🔐 Pro Tip: Combine ULID with proper time synchronization (like NTP) in distributed systems to ensure consistent ordering across all nodes.