Free ULID Generator - Create Sortable Unique Identifiers
Generate ULIDs (Universally Unique Lexicographically Sortable Identifiers) instantly for database primary keys, distributed systems, event sourcing, and API development. 26-character identifiers with millisecond precision and natural sorting.
About Our Professional ULID Generator
Our <strong>Professional ULID Generator</strong> creates Universally Unique Lexicographically Sortable Identifiers (ULIDs) - a modern, efficient alternative to traditional UUIDs. ULIDs are 26 characters long, use Crockford's Base32 encoding, and provide natural chronological sorting with millisecond precision.
ULIDs offer significant advantages over traditional UUIDs: Lexicographically sortable - they can be sorted as strings while maintaining chronological order, More efficient encoding - 26 characters vs 36 for UUID, URL safe - no special characters, Case insensitive - easier to work with, Monotonic sort order - correctly handles same millisecond generation, and Better database performance - reduces index fragmentation and improves query performance.
Common use cases include database primary keys, distributed system identifiers, event sourcing, logging systems, API development, microservices architecture, and any application requiring unique, sortable identifiers. ULIDs are particularly useful in distributed databases, cloud-native applications, and systems where chronological ordering and performance are critical.
For more information about ULID specifications and implementations, visit the ULID JavaScript implementation and ULID specification.
Technical Information
Advanced ULID Structure & Format
A ULID consists of two sophisticated components: a 48-bit timestamp (10 characters) representing milliseconds since Unix epoch, and an 80-bit randomness component (16 characters) ensuring uniqueness within the same millisecond. This structure provides both temporal precision and collision resistance.
Crockford Base32 Encoding
ULIDs use Crockford's Base32 encoding (0123456789ABCDEFGHJKMNPQRSTVWXYZ), which strategically excludes confusing characters like I, L, O, and U. This encoding scheme makes ULIDs more readable, less error-prone, and URL-safe compared to traditional hexadecimal encoding.
Natural Lexicographic Sorting
ULIDs are naturally sortable as strings because the timestamp component is encoded in a way that maintains chronological order when compared lexicographically. This makes them ideal for database indexing, sorting operations, and distributed system coordination.
Advanced Collision Resistance
ULIDs provide 1.21e+24 unique combinations per millisecond, making collisions practically impossible even in high-throughput systems. The 80-bit randomness component ensures uniqueness across distributed environments.
ULID vs UUID Comparison
| Length | Encoding | Sorting | Readability |
|---|---|---|---|
| 26 characters | Crockford Base32 | Naturally sortable | More readable |
| 36 characters | Hexadecimal | Not sortable | Less readable |
Applications & Use Cases
Database Design & Performance
Use ULIDs as primary keys in distributed databases for superior performance compared to UUIDs. Their sortable nature reduces index fragmentation, improves query performance, and eliminates the need for separate timestamp columns.
Event Sourcing & CQRS
Perfect for event sourcing systems where events need to be stored in chronological order. ULIDs provide natural ordering without additional timestamp fields, simplifying event store implementations.
Distributed Systems & Microservices
Create unique identifiers across multiple nodes and services without requiring centralized coordination. ULIDs work exceptionally well in microservices architectures and cloud-native applications.
Logging Systems & Monitoring
Generate unique log entry identifiers that maintain chronological order, making it easier to trace and debug distributed system issues across multiple services and environments.
API Development & REST Services
Use ULIDs for request IDs, resource identifiers, and transaction tracking in REST APIs and microservices. The URL-safe format and natural sorting improve API usability.
File Systems & Storage
Generate unique file identifiers that maintain creation time order, useful for file management systems, backup solutions, and distributed storage architectures.
Best Practices
Advanced Timestamp Usage
Use custom timestamps when migrating from existing systems, implementing data synchronization, or when you need specific time-based ordering. For new systems, let the generator use current time for optimal performance.
Performance Optimization
ULIDs provide superior database performance compared to UUIDs due to their sortable nature. They reduce index fragmentation, improve query performance in time-based queries, and eliminate the need for composite indexes.
Security & Cryptography
ULIDs generated with cryptographically secure random number generation are suitable for security-sensitive applications. The 80-bit randomness component ensures unpredictability and resistance to enumeration attacks.