fits

Compress PDF without uploading

Everything happens in your browser tab. Nothing is sent to any server. Watch the byte counter at the bottom — it stays at zero.

↑ 0 B of your file sent·↓ 0 B (page + engine)
Drop your PDF here
or click to browse · paste a copied PDF· up to 500 MB
fit under 500 KB · fit under 200 KB · pick your size

How compressing without uploading works

Every other 'free PDF compressor' works by uploading your file to a server, compressing it there, and sending it back. That means a copy of your document — passport, contract, medical record — sits on infrastructure you don't control, however briefly. fits. is built on the opposite premise: the compression engine runs inside your own browser tab via WebAssembly, so the file is never transmitted anywhere.

You don't have to take that on faith. Open your browser's Network tab, drop a PDF, and run a compression — you'll see the page and engine load, but no upload of your file. The site also ships a Content-Security-Policy that blocks cross-origin requests at the browser level, so the privacy guarantee is structural rather than a promise. The byte counter at the bottom of the page stays at zero for your document.

Common questions (5)
How can a PDF compressor work without uploading my file?
Modern browsers can run real compression code directly via WebAssembly. fits.tools downloads a small compression engine on your first visit (about 3 MB, cached for next time), then runs it on your file inside the same browser tab. No file ever leaves the tab.
How do I verify nothing is uploaded?
Open your browser’s Developer Tools → Network tab, then drop a PDF on the page and run the compression. You’ll see asset fetches for the page and engine, but no upload of your PDF. The site’s Content-Security-Policy header also blocks any cross-origin upload attempt at the browser level.
Why do other "free PDF compressors" require uploading?
Historically, browsers couldn’t run heavy compression code fast enough, so tools sent files to a server to do the work. WebAssembly (since 2017) and browser-side PDF libraries changed that. Most major compressors haven’t caught up — fits.tools is built around the new model from day one.
Is fits.tools really free, or is "free" the bait?
It’s free. There’s no signup, no daily limit, no watermark, no upsell. fits.tools has no document-handling server, which means almost zero cost-per-use to run — that’s what makes "free" actually free here.
What about confidential documents — passports, contracts, medical records?
Compressing them with fits.tools is exactly as safe as opening them in your own PDF viewer: the data stays on your device. No copy is made anywhere we control. That makes fits.tools appropriate for documents where the upload-then-trust model of other tools would be a non-starter.