Why on-device conversion is more private than uploading

An upload converter receives your video on someone else's computer and sends an MP3 back. OfflineMP3 is built the other way: the video you select is decoded and encoded in your browser. That is a real difference. It is not a claim that the website never touches the network.

Open the converter

What an upload converter has to see

If a site converts the file on its server, the file has to arrive there. Whoever runs that server can, as a matter of access, read the pictures, the soundtrack, the file name, and whatever metadata was inside. They may promise not to. The promise is a policy on top of the fact that the bytes were sent. A breach, a bug, a log line, or a change in the policy is a change in who has the file. You cannot audit that from the progress bar.

The same is true of an email attachment or a chat upload used as a workaround. The moment the video leaves the machine in order to be converted, the privacy question is about the recipient, their host, and their retention. OfflineMP3 does not offer that path. The product does not accept a media upload for conversion, and the terms tell you not to send a file to the server expecting one.

What this converter does with the file

You pick a local file. The page reads it into memory in the tab and writes it into the converter's private workspace in that same tab. Inspection, encoding, and verification all run there, in a Worker, using WebAssembly. The MP3 you save is written to a place you choose on your computer, or handed to the browser as a download. Your media file stays on your device. That is local, on-device conversion.

OfflineMP3 does not upload that file to its own server in order to convert it. There is no account the file could be attached to. The public Beta does not ask for your name, email, or a payment card in order to run the task. The contact address, support@offlinemp3.com, is for messages you choose to send. A message you send is the text you typed, not a copy of the video.

What still uses the network

The converter program is not built into the browser. The processing page downloads it, including the WebAssembly build, from the processing site. That transfer is the tool. It is not your video going up. If the program cannot be fetched, the task stops with a load failure. Your file was not the thing that failed to upload, because it was not uploaded.

The host that serves www.offlinemp3.com and app.offlinemp3.com sees the connection data any host sees: an IP address, a user agent, and the address of the page or asset you requested. This site does not claim the host throws all of that away. It does claim that this connection data is not a copy of the media file.

The processing page can show timing, worker counts, and a memory figure on your screen. Those numbers are for you, in that tab. The current converter does not send them anywhere. A future share control, described in the privacy policy, would send one privacy-minimized diagnostic event only if you chose it for that finished task. That control is not on the page today. The event, if it ever exists, is not allowed to contain the media, the file name, or a user identifier. Sending it would still be a disclosure. The product does not call it something stronger than that.

Where ads fit, and where they do not

Ads are a content-page concern. Third-party vendors, including Google, use cookies to serve ads based on a person's prior visits to this site and to other sites. Google's advertising cookies enable Google and its partners to serve ads based on those visits. You can opt out of personalized ads at https://adssettings.google.com, and you can read the industry opt-out page at https://www.aboutads.info.

A content page requests an ad only when the visit is on the production site www.offlinemp3.com, the visitor is estimated to be in the United States, the visitor has not opted out (a Global Privacy Control signal counts as an opt-out), and the site's advertising switch is on. If any of those is missing or uncertain, there is no ad request. The processing app at app.offlinemp3.com loads no ad script and sets no advertising cookie. An ad is not allowed to block saving a finished MP3, because the save happens on the other site, where the ad script is not loaded.

That split is the practical privacy point. The page that holds your video does not also hold an ad auction. The pages that may hold an ad do not hold your video. Opting out of personalized ads does not require an account here.

What this page will not claim

On-device conversion is more private than uploading the same file, because the file is not given to the operator's conversion server. It is not a magic circle around the whole browser. You are still talking to a website. Extensions you installed, your employer's device management, malware, or a person looking over your shoulder can still see a local file. The product does not control those.

The name OfflineMP3 refers to converting a file you already have, without sending it away to be converted. It does not mean the tab can do the job with the network unplugged from the first visit. The program has to arrive. After it has arrived, a later task in the same loaded page can run from that copy until the page drops it. The product does not promise a particular cache lifetime.

The full rules, including the diagnostic deletion credential that would exist only for a future opt-in event, are in the privacy policy. The terms say the same advertising limits in shorter form.