Explainpaper is a simple but powerful tool for anyone who struggles with the dense jargon and complex reasoning found in academic research papers. The concept is elegant: upload a PDF or paste in a paper, then highlight any sentence, paragraph, equation, or term you don't understand — and the AI provides a clear, plain-language explanation immediately. Beyond individual highlights, Explainpaper maintains a conversation thread for each paper. After getting an explanation, you can ask follow-up questions, dig deeper into specific concepts, or ask the AI to explain the explanation differently. It learns the context of the paper so its explanations remain grounded in the actual content rather than giving generic definitions. Explainpaper is used by PhD students navigating papers outside their sub-specialty, undergraduates reading primary literature for the first time, professionals tracking research in adjacent fields, and curious non-academics who want to engage with peer-reviewed science without needing a domain degree. The tool is deliberately minimal — no complex features, no learning curve. You upload a paper and start highlighting. This simplicity makes it accessible exactly where it matters most: when you are mid-read and encounter a concept that blocks understanding.