Locus

Locus is a browser extension that transforms how users interact with dense online content by enabling natural language search across web pages and PDF documents. Its core value proposition is to drastically reduce the time and cognitive effort required to find, understand, and retain key information from lengthy articles, research papers, textbooks, and documentation by leveraging AI to process and query content conversationally.

Key features: The tool allows users to ask questions in plain English about the content of any open webpage or uploaded PDF, receiving precise, synthesized answers with direct citations. It supports saving favorite pages and queries for quick recall, maintains a search history, and enables users to highlight and save important passages directly. A significant feature is the ability to bring your own GPT API key, allowing for cost control and access to different AI models like GPT-3.5, while the extension also offers role customization to tailor the AI's response style for specific tasks like summarization or technical explanation.

What sets Locus apart is its deep integration directly into the browser as a lightweight extension, focusing specifically on the pain point of navigating long-form digital content without requiring manual text copying or switching between applications. Unlike general-purpose chatbots, it contextually grounds its responses solely in the provided document or webpage, ensuring accuracy and preventing hallucinations. This technical approach of using the user's own API key for processing also offers greater privacy and flexibility compared to services with bundled, opaque AI costs.

Ideal for students, researchers, software developers, and professionals who regularly engage with complex documentation, academic papers, or lengthy reports. Specific use cases include quickly extracting methodologies from scientific articles, finding specific code examples in technical documentation, summarizing key points from online textbooks for study, and retaining crucial information from business or legal documents. It is particularly valuable in industries like academia, legal tech, software development, and any field reliant on dense informational resources.

The service operates on a freemium model. The core extension functionality is free to use indefinitely, though advanced features and higher usage limits, such as increased query capacity or team management, are available through a subscription starting from approximately $7.5 per month.