If nothing uploads, how does the site make money?

Advertising on the pages, planned below the tool, without interstitials. That is why the fast COEP-gated wasm build is off the table. The conversion itself is not a paid API. There is no conversion fee and no account wall.

Does the wasm engine phone home with my file?

The engine runs locally after it downloads. Your media is not an argument to the CDN. The CDN request is for ffmpeg-core.wasm or the UMD loader. You can use the self-hosted copies under /ffmpeg/ if the CDN path fails. Neither path is your movie leaving the tab.

Why is the first conversion slower?

The engine is about 25MB and downloads on first use. Later conversions in the same session skip that step. The media encode time is separate and scales with duration and whether the job is a remux or a re-encode.

Can I convert offline?

Partly. After the engine has downloaded, the transcode itself needs no network. Loading the page the first time still needs the site’s HTML and JS. There is no promise of a full PWA cache in this phase. Closing the tab drops the in-memory blobs either way.

Is local conversion a licence to copy anything?

No. You are responsible for holding rights to the files you convert. Processing on-device removes a third-party copy. It does not create permission you did not have. See Terms. A local MP3 of a commercial film is still a copy you may not be allowed to make.

Guide

Why online converters upload your files, and what that means for privacy

Most “online converters” upload because their ffmpeg runs on a machine they rent. The file has to get there. Videozify compiles ffmpeg to WebAssembly and runs it on the page, so the media never crosses the network. You can watch that in the browser’s Network panel.

If you want the local path on a real file, extract audio is a typical job: a home video or a meeting MP4 that you would not park on a stranger’s disk. Drop it, convert, and confirm no media upload appears. This guide is why the other sites cannot offer that, and what you still send when you load any website.

Why does a converter upload in the first place?

Because the encoder is a server process. An online converter is a remote service that needs your file on its disk before ffmpeg can run. Classic ffmpeg is a command-line program. Hosting it on a VM is the obvious product: receive a file, run a preset, write an output, offer a download link for an hour. That architecture requires an upload. Retention policies of “we delete after 24 hours” still mean the file existed on their disk.

It is also how those sites bill and throttle. A queue on their GPU is a meter. Videozify has no conversion queue because there is no conversion server.

What does in-browser conversion actually send?

The page HTML, JavaScript, CSS, and — on first convert — the ffmpeg engine, about 25MB of wasm. That engine may come from a CDN or from this site’s /ffmpeg/ folder. That is software delivery, not your movie.

Your dropped file is read with the File API into memory in this tab. The worker transcodes it. The output becomes a blob you download. Videozify does not have a media POST endpoint to accidentally hit.

Visiting the site still creates ordinary web requests: the document, assets, maybe future ads. Those requests are not the contents of the dropzone. Privacy policy covers that split.

Why not the “fast” multithreaded wasm build?

The multithreaded ffmpeg.wasm core needs SharedArrayBuffer, which needs Cross-Origin-Embedder-Policy: require-corp. That header breaks Google AdSense and most third-party ad scripts. Videozify uses the single-thread core and does not set COEP. Conversion is slower. A four-minute audio file might take eight seconds instead of three. That is the revenue-model trade, stated plainly.

The engine still must not load on first paint. It loads after you interact with the dropzone. If LCP waited on 25MB of wasm, the SEO project would fail and the privacy story would not save the bounce.

What Videozify will not do

It will not fetch a video from a URL you paste. There is no URL field. Fetching other people’s media is how converters become piracy tools and how ad networks dump you.

It will not mention YouTube, TikTok, or Instagram as a source. If you have a file you recorded or exported, drop the file. If you only have a link, this product is not the downloader.

It will not store conversions in an account. There is no account. Close the tab and the blobs are gone.

What you should still assume

Anyone with access to your device can see the file. Browser extensions can read a page. Corporate SSL inspection can see HTML you load, not the contents of a File object you processed locally — unless the extension itself reads the dropzone.

A bug in a future ad script could still be a problem on the page around the tool. That is why ads stay below the fold in a later phase, and why COEP stays off only with the slow core. Read Privacy when cookies exist. Today this build does not set advertising or analytics cookies.

How do you verify no upload?

Open DevTools → Network. Convert a short clip. You should see the engine wasm if it was the first job, then no multi-megabyte POST of your media. The download is a blob URL. That is the demo Videozify’s homepage describes.

If a site’s Network tab shows a large upload to storage.googleapis.com or similar during “conversion,” you are on the other architecture, whatever the landing-page copy said.

Are cookies the same problem as an uploaded movie?

No. A cookie can remember that you visited. An uploaded 80MB home video is the contents of the video. Videozify’s privacy page states the current cookie situation honestly: this build does not set advertising or analytics cookies.

When advertising is added, that page must name those cookies. The conversion architecture does not change when a banner appears. The dropzone still has no media POST. If a future script ever needed your file, that would be a product change, not a silent extra.

Corporate SSL inspection and browser extensions can still see HTML you load. They do not automatically receive a File object you processed locally. Extensions that read the page can still be a local risk. That is a device-trust problem, not Videozify inventing a server.

Frequently asked questions

If nothing uploads, how does the site make money?: Advertising on the pages, planned below the tool, without interstitials. That is why the fast COEP-gated wasm build is off the table. The conversion itself is not a paid API. There is no conversion fee and no account wall.
Does the wasm engine phone home with my file?: The engine runs locally after it downloads. Your media is not an argument to the CDN. The CDN request is for ffmpeg-core.wasm or the UMD loader. You can use the self-hosted copies under /ffmpeg/ if the CDN path fails. Neither path is your movie leaving the tab.
Why is the first conversion slower?: The engine is about 25MB and downloads on first use. Later conversions in the same session skip that step. The media encode time is separate and scales with duration and whether the job is a remux or a re-encode.
Can I convert offline?: Partly. After the engine has downloaded, the transcode itself needs no network. Loading the page the first time still needs the site’s HTML and JS. There is no promise of a full PWA cache in this phase. Closing the tab drops the in-memory blobs either way.
Is local conversion a licence to copy anything?: No. You are responsible for holding rights to the files you convert. Processing on-device removes a third-party copy. It does not create permission you did not have. See Terms. A local MP3 of a commercial film is still a copy you may not be allowed to make.