cobalt

cobalt is an open-source multi-platform media downloader maintained by imputnet, first released in 2021, licensed under AGPL-3.0 (copyleft), written primarily in TypeScript. It ships as both a Web UI and a REST API, covering YouTube, TikTok, Twitter/X, Bilibili, Vimeo, Instagram, Reddit, SoundCloud and 22+ more platforms for video, audio, and image downloads. The positioning is "no ads, no tracking, zero decision overhead" — minimalist download experience.

Core capabilities center on an API-first, self-host-friendly design. API mode is the default: feed a media URL, get back a direct link or a transcoded MP4 / WebM / mp3 / OGG. JSON over HTTP, batch-callable from scripts, ideal as a download node in an AI data preparation pipeline. Web UI mode is at cobalt.tools — paste a URL, one-click download, no cookies or tracking, multilingual UI maintained by the official and community. Platform coverage includes YouTube (av1 / vp9 / h264 / h265 adaptive selection), TikTok (watermark-free direct link), Twitter/X, Instagram Reels, Reddit, Bilibili (with regional cookie auth for HK/MO/TW/SEA), Vimeo, VK, Tumblr, Streamable, Rumble, Pinterest, Snapchat, Loom, Spotify (audio), and more. Self-hosting is first-class: official Docker / Node start scripts plus a protect-an-instance template for nginx + rate limit + Cloudflare Turnstile, suited for private cloud or home server deployments.

Use cases include: open-source developers self-hosting their own download service (replacing yt-dlp CLI dependency), AI training data preparation (API-batch fetches with metadata), content creators collecting reference material, and researchers monitoring platform data flows. Hardware floor: single-core CPU + 512MB RAM runs an instance if no local transcoding; local ffmpeg transcoding peaks at ~1GB memory. Onboarding: git clone → npm install → npm start, or docker run cobaltorg/cobalt; or use cobalt.tools (community-run, no official SLA).

Licensed under AGPL-3.0 (strong copyleft) — self-hosted instances must publish derivative source. If you only call a public instance as a client, AGPL doesn't apply. Commercial SaaS resale requires releasing your server code — this is the license delta versus yt-dlp (Unlicense). Compared to yt-dlp, cobalt's advantages are API-first design and a friendly Web UI, suited for non-technical users and scripted batch calls. Note: cobalt doesn't store any downloaded content; everything streams through. Copyright compliance is the user's responsibility under the target platform's ToS and the user's jurisdiction.