Question: I need a service that allows me to ask questions about multiple documents at once and get relevant answers - do you know of any?

If you're looking for a service that lets you ask questions about a group of documents, ChatDox is a good choice. This AI-based information retrieval system can converse with a broad range of document types, including PDF, DOCX, TXT and even multimedia sources like YouTube videos and audio files. It can accept multilingual queries and has other features like custom categories and live support through a Discord server. It's geared for a range of professionals, including students, researchers and lawyers.

Another good option is Hebbia, which offers a Large Language Model (LLM) foundation based on Matrix technology. Hebbia lets you ask questions of millions of documents at once, which makes it good for financial due diligence, market research and knowledge management. It can handle multi-file processing, verifiable AI and end-to-end encryption, so it's a good option for big businesses and industries like financial services and law.

If you're focused on PDFs, ChatPDF offers a more specialized service. You can upload PDFs and ask questions, and it'll return answers and summaries. It can handle multi-file chats, citations and PDFs in any language. That's useful for students, researchers and professionals who need quick answers from documents.

Last, Documind offers a custom chatbot trained on your PDFs so you can get answers directly from the content. It can handle bulk uploads of hundreds of PDFs, which is good for students and professionals who don't have a lot of time. The service touts data security and privacy, so your documents are protected and private.