What client-side file tools actually do

“Your files never leave your device” is easy to print on a landing page and hard to make true. This article is the definition we use at SW Commercial, with the exceptions named in the open.

The two architectures

An upload converter takes your file, stores it for a while, runs a job on a server, and sends a result back. You wait on a spinner that is actually someone else’s CPU. The company must then promise a retention policy, access controls, and a deletion story. Many of them are honest. The model still means they had the bytes.

A client-side converter sends the tool to you instead. The website delivers JavaScript, and WebAssembly where the job needs it. Your browser reads the file you chose with the File API. It compresses, converts, redacts, or builds a PDF on the device. When you click download, the new file is saved through the browser download manager.

SW Commercial is the second kind. For file tools, 0% of the file contents are meant to reach our servers. The full privacy policy is at sw-commercial.com/privacy.

What still travels over the network

The page itself has to load. That is HTML, CSS, JS, and sometimes a font or WASM codec (HEIC). A codec download is not your photo. Your photo is not attached to that request.

The host or CDN may record IP address, browser type, URL, and time. That is how sites stay up. It is not a copy of your invoice.

If Google AdSense is on, Google may use cookies to show ads. Ads are labeled. They do not receive the files you open in a tool. The SW Toolbox Chrome extension has 0 ads.

Optional analytics, if enabled, is a cookieless counter such as Plausible. It does not need the file.

Named exceptions, not fine print

Have I Been Pwned-style prefix checks are not on a live product on this domain today. If a later password tool ships, it will document that exception on its own page. Until then, do not open a tools.sw-commercial.com/cipher URL as if it were live.

Pro checkout opens Polar in a tab you choose. Polar Software, Inc. is the merchant of record. We do not store your card number. The Chrome extension does not call a Polar validate API; the key check runs on the device.

Those two cases are the network story. They are not a hidden upload path for HEIC, PDF merge, or JPEG compression.

How to test the claim yourself

You do not need to trust a slogan.

1. Open Tool Hub or another file tool.
2. Disconnect the network after the page has loaded (airplane mode on a phone, or unplug after the JS is cached).
3. Pick a throwaway file.
4. If the job still completes, the bytes did not need our server for that step.

First-time model downloads will fail offline until the model is cached. That is expected. It is still not an upload of your document.

Browser developer tools also show it. A converter that posts a multipart file to /api/upload is an upload converter. Our file tools are not built that way.

Why we still have a homepage, ads, and Pro

Client-side is a technical choice, not a vow of poverty. The apex catalog at sw-commercial.com lists the products. Some pages may show labeled ads. Free tools stay free. SW Toolbox Pro is $15 once if you want extra features in the extension. You can ignore Pro forever and keep converting.

What we will not do is mix the monetization path with the file path. Ads and checkout do not get a copy of the PDF.

What this is not

Client-side is not “we are invisible to the internet.” You still requested our HTML. Client-side is not a legal privilege that makes malware safe; you should still only open tools you chose. Client-side is not a guarantee that your next app is private — only that this family of tools was built so the file can stay put.

If a future product needs a server, we will say so on that product’s page. Until then, the default at SW Commercial is: send the tool, keep the file.

The SW Toolbox Chrome extension at tools.sw-commercial.com/extension keeps file jobs on the device as well. PlayNest kindergarten games are launching soon; this catalog does not send you to a host that is still returning an error.