ExpertX is a free iPhone app developed by Richard Demb in the Lifestyle category, focusing on Sports. The app allows users to provide personalized feedback through videos. Users can record feedback using their voice, lines, slow motion, or compare two videos easily. Additionally, users can decide whether to charge for their services and set the pricing.

To get started with ExpertX, users can download the app, input their area of expertise, add highlights about themselves, and upload a photo. The app then generates a personalized web page for the user. By sharing the link, anyone can upload their videos for review. Providing feedback is straightforward - users can record their voice and drawings, play, pause, and move through the video frame by frame using a three-button menu. Once satisfied, they can send the feedback back to the user.