PDFResources is an AI-powered search engine designed to help people find PDF documents from across the web. Its catalogue covers a wide range of subjects, including research papers, technical manuals, white papers, open-access books, textbooks, lecture notes, and practical guides. Users can search by topic, with AI query expansion intended to uncover relevant resources beyond basic keyword matches.

The service also checks links for PDF validity and file size, filtering out dead or misleading results, and lets users sort results by relevance or size. Browsing features include popular topic indexes and a catalogue of recent acquisitions, spanning fields such as science, engineering, law, business, computing, medicine, and the humanities. PDFResources also provides free online tools for common document tasks: merging files, splitting pages, compressing PDFs, converting PDF pages to images, turning images into PDFs, and adding text watermarks.

The site presents its search and tools as available without sign-up, offering a convenient starting point for discovering and managing PDF resources