To the average user, opening a PDF feels no different than viewing a webpage or reading a Word document. You see headers, paragraphs, multi-column articles, and neatly bordered tables. To a developer trying to extract structured data from that same PDF, it feels like staring into an abyss.
Source: [Dev.to](https://dev.to/tony_stark_h/how-pdf-document-parsers-actually-work-under-the-hood-16mp)