ULID Generator

ULID (Universally Unique Lexicographically Sortable Identifier) is a unique identifier format that combines timestamp and randomness. This tool helps you generate ULIDs that are both time-sortable and globally unique.

What is ULID?

ULID is a 26-character identifier that consists of:

First 10 characters: Timestamp (milliseconds precision)
Last 16 characters: Random values

Features

Time-sortable identifiers
Guaranteed uniqueness
Case-insensitive
URL-safe characters
No special characters
Fixed 26-character length

How to Use

Click the "Generate" button to create a new ULID
Use the copy button to get the generated identifier
Optionally generate multiple ULIDs in batch
View the timestamp information contained in the ULID

Use Cases

Database Primary Keys

Unique identifiers in distributed systems
Time-series data ID generation
Log event identification

Distributed Systems

Distributed task tracking
Message queue message IDs
Distributed lock identifiers

Business Applications

Order number generation
File naming
Session identification

Best Practices

Performance Considerations
- Ensure timestamp monotonicity in batch generation
- Use randomness appropriately to avoid conflicts
Application Integration
- Ensure system clock synchronization
- Consider timezone impacts
- Mind storage format compatibility
Maintainability
- Maintain consistent generation rules
- Establish ID format validation
- Keep proper documentation

Technical Specifications

Uses Crockford's Base32 alphabet (0-9, A-Z, excluding ambiguous characters)
Fixed length of 26 characters
Millisecond timestamp precision
Cryptographically secure random number generator for entropy

Important Notes

ULID relies on system clock, ensure server time accuracy
Consider generation strategy in high-concurrency scenarios
Recommended to use VARCHAR(26) for storage
Account for timezone conversion requirements