Are my video files uploaded to a server?

No. Processing runs inside your browser tab using WebAssembly FFmpeg, so your footage never leaves your device.

Which output format is best for sharing everywhere?

MP4 (H.264 + AAC) with faststart metadata plays smoothly across iOS, Android, macOS, Windows, and all social platforms.

Why does the first conversion take a few seconds to start?

Your browser downloads and caches the ~31 MB FFmpeg WebAssembly core once. Subsequent conversions start immediately.

What file size works best in the browser?

Clips under 200 MB convert smoothly within standard browser RAM limits; very large 4K files may require desktop software.

Video Tools100% Client-Side4.8 (412 ratings)

Video Converter

Built for creators, educators, and developers who need fast format conversion without uploading private footage to external servers.

Drop an MP4, WebM, MOV, MKV, or AVI video here

Processed 100% locally in your browser via WebAssembly FFmpeg — zero server uploads

How to Use Video Converter

1Drop or select an MP4, WebM, MOV, MKV, or AVI video from your device.
2Choose your target output container (MP4, WebM, MOV, AVI, or MKV).
3Optionally downscale resolution to 1080p, 720p, 480p, or 360p.
4Click Convert and download your finished video with zero watermarks.

Key Features

Supports MP4 (H.264), WebM (VP8), MOV, AVI, and MKV outputs
Optional resolution scaling (1080p, 720p, 480p, 360p)
100% browser-based WebAssembly FFmpeg execution
Zero file uploads and no watermark added

Private In-Browser Video Transcoding With WebAssembly

Traditional online video converters upload multi-megabyte recordings to remote servers, queue jobs behind paywalls, or stamp logos across your export. By running FFmpeg compiled to WebAssembly directly in your browser memory, ToolCix keeps unpublished screen recordings, family clips, and client footage strictly on your own device.

Whether you need to turn a QuickTime MOV capture into a web-ready MP4 or transcode a clip into open WebM for HTML5 embeds, you can switch formats and downscale resolutions in a single clean workflow.

Choosing the Right Container and Resolution

Pick MP4 (H.264) for maximum compatibility across mobile messaging apps and CMS uploads, WebM for lightweight browser playback, or MKV/MOV for editing pipelines. If your converted clip is still too large for email or Discord, run it through our Video Compressor next.