🛠️ How to Run a Privacy-First, Browser-Based Stream Downloader (FlowPick) — A Hands-On Tutorial

Hey folks 👋 If you've ever wanted to save a video lecture, a livestream replay, or a podcast episode for offline listening, you've probably run into the usual options: sketchy "online video parser" websites that ask you to paste your link into their server, or desktop apps that want you to sign up and upload stuff. Neither feels great when the whole point is your content. I went looking for something better and ended up working with FlowPick — an open-source, privacy-first media downloader that runs entirely in your browser. No uploads, no accounts, no telemetry. Everything (sniffing, downloading, merging, transcoding) happens client-side with FFmpeg compiled to WebAssembly. In this tutorial we'll: Clone and run FlowPick locally Download our first HLS ( .m3u8 ) and DASH ( .mpd ) stream Build and deploy it Poke at the internals so we can customize it If you just want to try it without installing anything, there's a hosted version at https://flowpick.net (more below). The full source is on GitHub: https://github.com/ezwebtools/flowpick . 🔗 Repo: https://github.com/ezwebtools/flowpick · Live tools: https://flowpick.net A 30-second primer: what are HLS and DASH? Before we touch code, two words you'll see everywhere in this space: HLS (HTTP Live Streaming) uses a .m3u8 manifest that lists small .ts (or fMP4) segments. Common for live streams and a lot of video platforms. DASH (Dynamic Adaptive Streaming over HTTP) uses a .mpd manifest; video and audio usually travel as separate .m4s tracks. YouTube and Bilibili lean on this. The key idea: the "video" isn't one file. It's a playlist pointing at dozens (sometimes hundreds) of tiny segments. A downloader's job is to fetch all the segments, decrypt them if needed, and stitch them back into one playable file. That's exactly what FlowPick does — in the browser. What FlowPick is, in one paragraph FlowPick is a Nuxt 4 app that ships in two shapes: A browser extension that sniffs media from the current tab's network requests. An