Flatten a PDF
Flatten PDF bakes form fields, annotations and stamps into the page so they can't be edited or accidentally changed — the file looks the same but becomes fixed. Perfect before sharing a completed form or a signed document.
Flattening is done locally, keeping your finished document on your own machine.
How to flatten a PDF in three steps
- Open the PDF with fields or annotations.
- Flatten it to merge those layers into the page.
- Save and download the flattened PDF.
Why Flatten PDF runs on your device
Everything happens on your device. The moment you choose a file, Flatten PDF loads it directly into your browser's memory and does all the work there with WebAssembly and JavaScript — the bytes never travel to a server, because there is no server in the loop. FreePDFX enforces a strict Content-Security-Policy whose connect-src 'self' rule makes it physically impossible for this page to send your document anywhere, even by mistake. Want proof? Open your browser's Network panel and watch, or simply switch off Wi-Fi first. As an installable Progressive Web App, it keeps working fully offline once the tools are cached. FreePDFX sets no advertising or analytics cookies today, and keeps only small settings you can see and wipe any time — your PDFs are never among them, because they are never received.
Lossless — nothing is re-encoded
This is a lossless operation. Your original pages are copied byte-for-byte into the result, so text stays selectable, images keep their exact quality and vector graphics stay razor-sharp — nothing is rasterised, re-compressed or downgraded. Flattening draws each field and annotation from its existing appearance into the page, preserving how the document looks while locking it in place.
Free forever, with no sign-up and no watermarks on your results. FreePDFX exists to give you the everyday PDF tools you need without handing your documents to a stranger's server. Every tool is honest about what it can and cannot do, so you always know whether you are getting a byte-perfect result or a solid best-effort one before you download.
Frequently asked questions
Are my files uploaded anywhere?
No. Flatten PDF runs entirely inside your browser. Your file is opened in local memory and processed with WebAssembly and JavaScript, and the site's Content-Security-Policy blocks every network connection except to FreePDFX's own files — so your document simply has no route off your device.
Does this work offline?
Yes. FreePDFX is an installable Progressive Web App. After your first visit the tools are cached, so you can add it to your home screen or desktop and keep using Flatten PDF with the Wi-Fi off — nothing needs to download again.
Is there a file size limit?
There's no server-side limit, because nothing is uploaded. The only ceiling is your own device's memory: very large or high-resolution PDFs use more RAM, so an older phone handles less than a modern laptop. If a huge file struggles, close other tabs and try again.
Do I need to sign up or pay?
No. FreePDFX is free and needs no account, email or payment. Open a file and go — there's nothing to register, and no watermark is added to your results.
Why would I flatten a PDF?
To lock in a filled form or signature so it displays consistently everywhere and cannot be altered or cleared by another reader.
Can I edit the fields after flattening?
No. Flattening is meant to make them permanent, so keep an unflattened copy if you might need to change them later.