HotRepo is a web-based directory that tracks the fastest-rising open-source projects on GitHub Trending. It ranks repositories by the number of stars gained and provides a short AI review for each entry. The site states that its listings are updated every 30 minutes. Its primary function is to help users discover and monitor rapidly gaining GitHub projects through a concise, ranked daily board. The service includes a Trending on GitHub today board, a Recently off the board section, date-labeled views such as Last on Nov 2, topic browsing, past-day archives, and a feedback and suggestions channel. Individual listings show the repository name, star gain, a brief AI review, and metadata such as primary language, total stars, forks, repository age, topic tags, and daily ranking position. Projects are organized into categories such as Developer Tools, Finance, and Machine Learning. Examples of covered repositories include composable agent skills for coding agents, a pretrained model for K-line price and volume forecasting, and a minimal codebase for training a GPT-2-class language model. A typical workflow is to open the daily board, scan star gains and AI summaries, select a repository, and follow the link to GitHub for source code and documentation. Users can also browse by topic or review past days to identify longer-term trends. HotRepo functions as a discovery layer for GitHub repositories rather than as a repository host. It is a web-based service, and the provided content does not state any installation or account requirement.