A permalink is a permanent URL assigned to a specific piece of content on the web, designed to remain stable and unchanged over time. The term is a portmanteau of "permanent link," and the core idea is straightforward: once a URL is published and indexed, it should continue to resolve to the same resource indefinitely.
Permalinks in WordPress
The concept is especially prominent in WordPress, where permalink settings determine how the platform constructs URLs for posts, pages, categories, and other content types. By default, older WordPress installations used a query-string format such as example.com/?p=123, which is functional but carries no descriptive information. WordPress allows site owners to switch to more readable structures, such as example.com/category/post-title or simply example.com/post-title, through the Permalinks settings panel. The readable portion at the end of the URL is commonly referred to as a URL slug.
Why URL Stability Matters for SEO
From a technical SEO perspective, permalink stability is a foundational concern. Search engines like Google assign ranking signals to specific URLs over time. When a page accumulates backlinks, social shares, and crawl history under a given address, all of that authority is tied to that exact URL. Changing the URL - even slightly - causes search engines to treat the destination as a new, unrecognized page, effectively resetting its accumulated equity.
When a URL change is unavoidable, a properly configured 301 redirect can transfer the majority of a page's ranking signals to the new address. However, this process is never perfectly lossless, and some link equity is typically lost in the transition. This is why choosing a sound permalink structure from the outset is strongly preferred over restructuring URLs after a site has been indexed.
Choosing a Good Permalink Structure
A well-formed permalink is both human-readable and descriptive. Including relevant keywords in the URL slug can provide a minor but meaningful SEO signal, and it makes links easier for users to interpret before clicking. Most SEO guidance favors concise, keyword-focused structures - such as example.com/permalink-seo - over structures that include dates, category hierarchies, or auto-generated numeric identifiers, as these tend to become outdated or unwieldy over time.
It is also worth noting that permalink stability extends beyond individual blog posts. Product pages, landing pages, and documentation articles all benefit from consistent, long-lived URLs. Any content that is intended to attract organic traffic or external links should be treated as a permanent resource, with its URL chosen carefully and changed only when absolutely necessary.