Glarity

Glarity is an open-source ChatGPT extension for Chrome, Edge, Safari, Firefox and Opera. It summarizes YouTube videos with timestamped highlights and subtitles, condenses web pages, Google results, PDFs and Gmail threads, translates pages side by side, and offers AI chat with GPT-4o, Claude 3.5 and Gemini Pro.

Glarity is a browser extension that puts a ChatGPT-style assistant beside whatever you are reading. Its headline job is video work: on YouTube it generates a summary in more than a dozen languages, builds timestamped highlights so you can jump to the part that matters, produces an FAQ for the video, and can generate or translate subtitles. The same panel opens on ordinary web pages, Google results, PDFs, Twitter threads and Gmail, so a long article, a search page or an inbox thread can be condensed without leaving the tab. The extension is built for people who read and watch across languages. A full-page translation mode works side by side with the original, and it also handles selected text, PDF selections and text inside images. An AI reader layer lets you ask questions about a PDF or a page and get answers drawn from that content rather than from general model knowledge. A free writing assistant rounds things out for drafting articles, emails and social replies. There is also a standalone chat surface with a model picker. The site advertises access to GPT-4o, Claude 3.5 and Gemini Pro, a 200k context window and unlimited image generation inside the chat product. Users who already pay for an OpenAI key can plug it in; the extension is open source and can also run on Glarity's own hosted models. In practice Glarity competes less with full chatbot suites and more with other summarizer extensions. It wins on breadth: one install covers video, search, documents and translation instead of four separate tools. It is a sensible pick for students, researchers and multilingual readers who want a fast gist without copy-pasting links into a separate app. Buyers who only need video summaries may find a lighter single-purpose tool less cluttered, and anyone who needs deep document workflows should test the PDF chat against a dedicated reader before committing. The site reports more than one million users and lists Chrome, Edge, Safari, Firefox and Opera builds.