cuid is a collision-resistant ID generation library optimized for horizontal scaling and binary search lookup performance.
The tool addresses the need for unique identifiers in distributed systems where multiple hosts generate IDs independently without central coordination. It combines a timestamp, a counter to handle rapid successive generation, a client fingerprint derived from system characteristics, and random data to create short strings suitable for use as HTML element IDs and database record lookups. The approach was designed to support modern applications requiring online/offline capability and horizontal scalability across multiple machines.
Developers should be aware that this project is deprecated due to security vulnerabilities. The README explicitly states that cuid leaks timestamps and recommends using cuid2 instead. The documentation notes that all monotonically increasing IDs and timestamp-based schemes share similar security issues, and demonstrates real-world exploits where guessable IDs have enabled unauthorized password resets and unauthorized access to private resources. The tool remains available across multiple language implementations including Node, browsers, Java, Ruby, .Net, and Go, but new projects should not adopt it.
The project is no longer actively maintained, with development having concluded before the deprecation notice was added to the repository.
