The SEC allows people to access data without an API, but it's through the raw text or XBRL. XBRL has XML syntax, but it's not standardized. This means it's only marginally more useful than raw text. For a while, companies may have been reporting things incorrectly in XBRL (https://en.wikipedia.org/wiki/XBRL#Lack_of_accuracy).
Because of this terrible dataset, a few companies have emerged to either provide a better SEC API, or to help with the analysis as well, like