Edit a video without uploading it

How can I verify AetherCut does not upload my video?

Open DevTools, use the Network tab, then import, cut, and export a video in AetherCut. Filtering requests by Media or XHR shows zero outbound video bytes, and the video stays on your drive with an exported copy in Downloads.

Open DevTools (F12). Click the Network tab. Open the editor at aethercut.app. Drop a video onto the timeline, make a cut, export. Filter the network log by Media or XHR.

The count of outbound video bytes is zero. The file you dropped is still on your hard drive; a second copy now exists in your Downloads folder. Nothing ever crossed the network.

Why do most browser video editors upload files?

Many browser editors were built before browser video processing became practical, so they used server side workflows. AetherCut was built around WebCodecs and FFmpeg.wasm, so uploading was never part of its design.

Browser-based video processing didn't exist until WebCodecs landed in Chrome 94 and Safari 17 made FFmpeg.wasm viable. Most editors built before then took the easier engineering path: upload the file, process server-side, return an MP4. That architecture is stuck with them today.

AetherCut started from the WebCodecs / FFmpeg.wasm starting line. The editor was built to use the browser's capabilities, so the upload step was never part of the design.

Does AetherCut ever send anything to a backend?

Some optional AI features do. Auto captions sends audio to Whisper, and AI B roll sends a text prompt to Kling. Privacy Mode disables all of them, while standard editing like cut, trim, color, and export uploads nothing.

Some AI features do call our backend by design (auto-captions sends audio to Whisper, AI B-roll sends a text prompt to Kling). These are opt-in, individually toggled, and Privacy Mode disables all of them at once. The default state of the editor — cut, trim, color, export — uploads nothing.

What actually happens on your device when you edit without uploading?

When you import a file into AetherCut, the browser gets a local handle to that file and reads it directly on your machine. The editor can then decode frames and audio in the browser, render previews, and apply timeline changes without needing a round trip to a server. That distinction matters because “no upload” is not just a marketing phrase here; it means the work of opening the file, previewing edits, and generating the finished export is performed by your device instead of a remote backend. The practical result is that your internet connection is not the bottleneck for normal editing, and disconnecting from Wi‑Fi after the app loads will not suddenly force an upload step for basic cuts and exports.

A common source of confusion is assuming any visible network activity means the video was sent somewhere. It usually does not. Your browser may still request the app shell, fonts, analytics-blocked assets, or optional AI endpoints if you explicitly use those features. None of that is the same as transferring the media file itself. If you want a clean test, load the editor, wait for the interface to finish loading, then start recording in DevTools before you import the video. After that, trim a section, move a cut point, and export. What you are checking is whether the file contents leave the machine during the edit flow, not whether the page makes any request at all.

Another mistake is testing with cloud-synced folders and then blaming the editor for background traffic. If your source video lives in iCloud Drive, Dropbox, OneDrive, or Google Drive for desktop, those apps may sync the file independently of AetherCut. The same goes for your Downloads folder after export. For the clearest privacy check, use a file stored in a purely local folder and pause any sync client during the test. That isolates the editor’s behavior from everything else running on your system.