YouTube Summary & ChatGPT by Glasp

YouTube Summary & ChatGPT is a free Chrome extension from Glasp Inc. that injects a sidebar widget into YouTube pages, exposing the full transcript and an on-demand AI summary of the current video. It also adds a toolbar button that opens ChatGPT in a side panel so you can query a model without jumping tabs, and it lets you pick between GPT-3.5, GPT-4, Claude, Mistral, and Gemini as the summarization backend.

The extension is aimed at researchers, students, and content curators who want to skim long videos, pull timestamped highlights, or feed a transcript into their own prompt. Glasp's broader product is a social highlighting tool, and this extension is essentially a funnel into that ecosystem; it's free with optional in-app purchases for premium features. With 100,000+ users and a 3.9-star rating across 187 reviews, it's a mid-tier player in a crowded niche of YouTube summarizers.

Summary length and prompts are customizable, transcripts are copyable in one click, and timestamp links jump you back into the video. The catch is that you're bringing your own API key or relying on the free tier for the heavier models, and the 3.9 rating reflects the usual complaints about transcript availability on certain videos and occasional model errors.