How it works

Your browser does the work

Most online converters upload your file to their servers, process it there and send it back. Okaysize doesn't. When you open a tool, your browser downloads the tool's code, the same way it downloads the page. Your file is then read and processed on your own device, and the result is saved straight to it.

That's why there's no upload wait, no queue and no file size limit: we never receive your file, so it costs us nothing to process.

What runs where

• Video and audio use WebCodecs, the video and audio encoders built into your browser and often your device's hardware. Files are read in pieces straight from disk, so even very large videos don't have to fit in memory.
• Images use Squoosh's open source codecs (MozJPEG, WebP, AVIF and OxiPNG), compiled to WebAssembly.
• PDFs are rebuilt with pdf-lib, recompressing the images inside them.
• All of it runs in background workers, so the page stays responsive while your file is processed.

Check it yourself

You don't have to take our word for it.

• Open a tool, then open your browser's developer tools (F12, or right click and choose Inspect).
• Go to the Network tab and clear it.
• Drop a file and process it.
• Look through the requests. You'll see code and engine files load from okaysize.com, but nothing that sends your file anywhere. For extra certainty, turn off your internet after the page loads: the tools keep working.

What we do collect

We count anonymous events, like "a video was compressed" with the tool name, a rough size bucket such as "10 to 100 MB" and how long it took, so we know what to improve. We never collect file names, contents, dimensions, durations or any other detail about your files. The privacy policy lists everything.

Open source inside

Okaysize is built on excellent open source software, including mediabunny, Squoosh's codecs, pdf-lib, pdf.js and gifenc. The licenses page lists every library and its license.