YouTube Downloader

Download any YouTube video or audio directly — CLI tool and full-featured web app.

Hits YouTube's internal Innertube API the same way the official apps do. Pulls every available format, resolution, and codec. Works on Linux, macOS, and Windows.

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Web App — youtubeone.vercel.app

A privacy-first YouTube downloader that runs entirely in your browser. No sign-in, no tracking, no file upload.

Features

• Smart Merge — merges a high-quality video-only stream with audio using ffmpeg compiled to WebAssembly, completely in-browser. Supports up to 4K.
• Dubbed language picker — when a video has dubbed audio tracks (e.g. Hindi, Spanish, French…), Smart Merge shows a second dropdown so you can pick exactly which language to pair with the video. The original language is always pre-selected. No other public downloader exposes this.
• All formats — three tabs: Video + Audio (pre-muxed up to 360p), Video Only (up to 4K, no audio), Audio Only (original language, all bitrates).
• No upload — your video never leaves your device. ffmpeg runs locally via WebAssembly.
• Fast — ffmpeg stream-copies both tracks (no re-encode), so muxing a 1 GB 4K file takes a few seconds.

How Smart Merge works

1. Paste a YouTube URL and hit Enter.
2. Open the Video + Audio tab — Smart Merge appears at the top.
3. Choose video quality from the first dropdown.
4. If the video has dubbed tracks, a language dropdown appears — choose the audio language.
5. Hit Merge & Download. ffmpeg loads (cached after first use), fetches both streams, muxes them in-browser, and saves Title [1080p] [Hindi].mp4 to your downloads.

Extraction routing

YouTube bot-blocks datacenter IPs, so the deployed app does not call YouTube from Vercel directly. Xray-core runs inside the same container as the Next.js server and exposes one local HTTP proxy port per VLESS node.

Vercel container
├── Xray-core      127.0.0.1:10809+i  →  VLESS/REALITY  →  exit IP i
└── Next.js        picks an exit per request

A request picks a random exit, retries on another if the first is refused, and the chosen node index travels with the response so /api/stream downloads through the same exit — YouTube signs CDN URLs against the requesting IP.

The node list reads at boot from the VLESS_NODES environment variable, one vless:// URI per line. See web/.env.example.

Variable	Purpose
VLESS_NODES	Node list, one URI per line (required)
XRAY_BASE_PORT	First local proxy port, default 10809
PROXY_TIMEOUT_MS	Per-request tunnel timeout, default 20000
YTDL_DEBUG	Set to 1 to log which exit and client answered

Deployment is a container build (web/Dockerfile.vercel) rather than the default Next.js build, because Xray has to run alongside the server.

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CLI Tool

Download any YouTube video or audio directly from the terminal — no API key, no dependencies.

Run it

# Linux / macOS
go run .

# Windows
build.bat

# Non-interactive (downloads best video)
go run . https://www.youtube.com/watch?v=VIDEO_ID

Options

Flag	Description
-o <dir>	Custom output directory
--cookies <file>	Netscape cookies.txt for private/age-gated videos
--proxy <url>	HTTP/SOCKS5 proxy URL

Build binaries

# Linux
CGO_ENABLED=0 go build -o ytdl .

# Windows (cross-compile from Linux/macOS)
GOOS=windows GOARCH=amd64 CGO_ENABLED=0 go build -o ytdl.exe .

Go 1.22+ required. Zero external dependencies.