I was tired of manually copying YouTube transcripts, so I built a 15KB Firefox extension

If you rely on YouTube for learning, research, or AI tool development, you are likely familiar with the inconvenience of manually copying transcripts. The process involves opening the transcript panel, scrolling, selecting all text, avoiding copying the entire page, pasting it into notes, and then fixing formatting. I perform this task multiple times daily, which led me to create yt-transcript-yoinker, a compact Firefox add-on that adds a "Copy Transcript" button directly into the YouTube interface.

With a single click, the entire transcript becomes available in your clipboard, without the need for an account, external API, or data leaving your device. You can find the source code on GitHub (https://github.com/pawanhirumina/yt-transcript-yoinker/) and install it from the Mozilla Add-ons store (https://addons.mozilla.org/en-US/firefox/addon/yt-transcript-yoinker/).

The motivation behind this tool was clear: I needed transcripts for my study notes, lecture summarization using Large Language Models (LLMs), and creating subtitles or documentation. Existing solutions either required pasting a YouTube link into a questionable website, sent data to a server, or were overly complex extensions that requested permission to access all my data. I wanted a simple, local solution that just worked.

One-click copy functionality adds a button next to the video title or description, which appears only when a transcript is available. The feature is private, ensuring that all processing occurs within your browser, with no data transmitted to a backend. The extension is lightweight, weighing only 15 KB after packing, relying solely on vanilla JavaScript and WebExtension APIs. It is open source, licensed under the MIT license, making it easily auditable.

Under the hood, the content script listens for YouTube navigation completion. It checks for the presence of a transcript endpoint for the specific video ID. Upon clicking the new "Copy Transcript" button, it fetches the same JSON transcript data that YouTube's native transcript panel uses, formats it into plain text with timestamps, and then copies it to your clipboard using navigator.clipboard.writeText().

The entire extension consists of approximately 100 lines of JavaScript code. While the initial development was targeted at Firefox, due to the platform's strict privacy review process, a Chrome version is planned for the future. Developers interested in contributing can find the source code on GitHub and follow the installation instructions provided.