A URL is not a DOI, but both serve as locators of digital content, and within APA Style (both 6th and 7th editions), their use reflects not just technological convenience but a philosophy of retrievability and stability, two pillars of scholarly citation; as per the APA 6 guidelines archived by the Purdue OWL, a URL may be included at the end of a reference entry to direct readers to a webpage or online document, provided the material is stable and publicly accessible, however, a DOI (Digital Object Identifier) is preferred over a URL precisely because it is persistent, standardised, and globally managed by a central authority—unlike URLs which are susceptible to rot, redirects, or deletions; the Purdue guide clarifies that when a DOI is assigned to an article or book, it should be cited regardless of whether the source was accessed online or in print, while URLs should only be used if no DOI is available, and only when the source is hosted in a durable online format such as an institutional repository, open-access platform, or public blog, and notably APA discourages including access dates unless the content is likely to change (e.g. wikis); the semantic difference between URL and DOI in APA is thus functional rather than technical—DOIs assert stability and precision, whereas URLs imply utility without guarantee, which is why URLs are often omitted for sources from academic databases or journals that can be found via common retrieval methods; so, although a URL may “look” like a DOI in form—both begin with “https://” and end a reference entry—it lacks the referential permanence and standardisation that makes DOIs the gold standard for citable electronic resources in scholarly work.
Purdue Online Writing Lab. (n.d.). Reference list: Electronic sources (web publications). Purdue OWL. Retrieved from https://owl.purdue.edu/owl/research_and_citation/apa6_style/apa_formatting_and_style_guide/reference_list_electronic_sources.html
