URLid

URLid is a term used in web development to denote a unique identifier embedded in a URL that references a specific resource in a system. It may appear as a path segment, such as /articles/12345, or as a query parameter, such as /products?id=12345. Formats include opaque numeric IDs, UUIDs, or slug strings that are more readable. URLids enable stateless resource addressing, improve bookmarkability, and support efficient caching by ensuring a direct route to a resource.

In practice, URLids are used across content management systems, e-commerce sites, and APIs to locate items such as articles, products, users, or records. They can be designed to be opaque to avoid exposing internal database structure, or human-readable (slugs) to improve SEO and usability. When using URLids, the server should not rely on the client for authorization; the ID is merely a pointer to a resource that must be verified against permissions.

Design considerations include choosing between path segments and query parameters, choosing ID format (incrementing, UUID, slug), and handling localization. Slugs improve readability; opaque IDs reduce enumeration risk. Caching strategies and canonical URLs should be planned to avoid duplicate content and ensure consistent resource representation.

Security and robustness: validate and sanitize IDs, handle URL encoding, escape where necessary, and defend against injection or path traversal. Do not expose sensitive information in the URL. Use access controls to ensure that an ID cannot be meaningfully exploited. Consider rate limiting and auditing for URL usage.

Related concepts include RESTful resource identifiers, slugs, and opaque identifiers. URLid practice aligns with RESTful design by treating resources as addressable via a stable URI; it is a common pattern across web APIs and modern web applications.