Short answer: yes. Your files are read, converted and saved inside your browser, on your device. They are never uploaded. Here's how that works, how to check it in 30 seconds, and what no website can promise.
What happens when you drop a file
- Your browser reads the file locally. When you choose or drop a file, the page gets access to it through the browser's File API. Nothing is sent: reading a file is not the same as uploading it.
- The work runs in a background worker. The image and PDF engines are compiled to WebAssembly, a format browsers run at near-native speed. They run in Web Workers, so a big batch doesn't freeze the page.
- The result is made on your device. The new JPG, PNG or PDF is created in your browser's memory and offered as a normal download. A ZIP of many results is built the same way.
The engines are the same open-source libraries many desktop apps use: MozJPEG, libwebp, libavif, OxiPNG and the Squoosh resizer, libheif for iPhone photos, pdf-lib and Mozilla's PDF.js. They are downloaded from this site the first time a tool needs them, and then kept by your browser. See Open-source licences.
Check it yourself in 30 seconds
- Open a tool, for example HEIC to JPG or Compress PDF, and use it once (so its engine is loaded).
- Turn on airplane mode, or unplug from the internet.
- Convert another file. It still works, because nothing needs to be sent anywhere.
On a computer you can also watch the traffic: open your browser's developer tools (F12), go to the Network tab, and convert a file. You'll see the tool's own code files the first time, and no request that carries your file. A converter that uploads would show a large outgoing request the size of your file.
What the site still loads
Being honest about this matters more than a slogan. Like any website, the pages load their own code, fonts and images from this site, and the tools load their engines the first time you use them. The site also counts anonymous daily totals (which tool was used, never anything about your files), counts page views with Cloudflare Web Analytics (no cookies), and may show Google ads, which load Google's ad code on the page as on any site with ads. Your files are never given to any of these. The details are on the Privacy page.
If you want the strictest setup, install the app, use the button there to download every tool once, and use the tools offline.
What no website can promise
- Your device itself. Browser extensions you've installed can read pages you visit, and malware on a device can read anything. A website can't protect you from those.
- Where the downloads go. Results are saved like any download. If your downloads folder syncs to a cloud service, the results will sync too.
- What you do next. Uploading the result to a form or a social network is a separate step, with that service's own rules. Removing photo details such as the location first is a good habit.
Why other converters upload
Many online converters send your file to their server, convert it there and send it back. That's simpler for them to build, and it's why they limit file sizes, count conversions per day and keep you waiting in a queue: every file costs them server time. Here, your own device does the work, so there's nothing to limit and nothing to queue.