Built a cross-platform desktop app (Electron + Next.js) that saves Instagram reels and videos straight to disk — paste a link, pick a quality, get a clean .mp4. Runs entirely on the user's machine with zero servers, wrapping yt-dlp and FFmpeg for fetching and automatic audio/video muxing behind a hand-drawn 'paper notebook' UI (rough.js) with real download progress and a queue. Ships Windows and macOS installers through a GitHub Actions release pipeline, with Vitest unit tests and fast-check property-based suites covering error mapping and quality ordering.
