From Sci Space - "SciSpace is the easiest way to find, understand, and learn any research paper. For every paper you read, get simple explanations and answers from AI and discover a network of connected and relevant papers — all in one place.
We believe scientific breakthroughs are better served when they happen ahead of time. But every day, researchers worldwide waste their precious time sifting the internet for relevant information, formatting and reformatting papers, among other mindless tasks.
This is where SciSpace comes in. Our end-to-end purpose-built workspace enables researchers, publishers, and institutions to collaborate and work efficiently, automate repetitive tasks, and discover information quickly. As a repository of research papers across domains — with metadata of 200 million+ papers and 50 million+ Open Access full-text PDFs, we are dedicated and focused on designing features that simplify research discovery and learning."

From Perplexity - "Perplexity is a free AI search engine designed to revolutionize the way you discover information. Ask any question, and it searches the internet to give you an accessible, conversational, and verifiable answer. Think of Perplexity as a research partner, always on the clock, saving you valuable time by providing the precise knowledge you need."