NimTube is a client-side open-source YouTube downloader and audio converter that runs entirely in your browser using 64-bit Mediabunny and WebCodecs. It bypasses server throttling and downloads videos directly to your device.

How does NimTube download 4K and 1080p YouTube videos?

YouTube serves 1080p and 4K video streams separately from audio streams. NimTube downloads both streams in parallel 8MB chunks using browser workers, and muxes them locally using 64-bit Mediabunny without server re-encoding.

Can I convert YouTube videos to MP3 with NimTube?

Yes, NimTube allows you to download and extract audio from YouTube videos directly into high-quality MP3, AAC, or WAV format.

Is NimTube free and secure?

NimTube is 100% free, open source, and privacy-focused. All downloads occur directly between your browser and YouTube's CDN. No video data passes through any third-party server, and its extension has 0/64 clean detections on VirusTotal.

NimTube — Pure Client-Side YouTube Studio & Downloader

NimTube is an open-source, client-side YouTube video downloader and audio converter. Download YouTube videos in 4K 60fps, 1440p, 1080p, and convert audio to 320kbps MP3 directly in your browser without proxy servers, queues, or speed limits.

Core Features

Pure Client-Side: Streams directly between YouTube CDN and your local browser using your own residential IP.
4K & 1080p Lossless Muxing: In-browser 64-bit Mediabunny merges separate audio/video streams losslessly with zero quality loss (passthrough).
Throttling Bypass: Adaptive parallel chunk streaming defeats YouTube bandwidth throttling.
Direct-to-Disk: Streams incoming chunks straight to local storage via File System Access API with low memory usage.
Audio Extractor: Local extraction and high-quality saving to M4A, MP3, or WebM.
Open Source & Clean: 0/64 clean score verified on VirusTotal.

Documentation & Links

How It Works & Technical Architecture
NimTube Bridge Chrome Extension Guide
Release Notes & Version History
GitHub Repository (MIT License)