Flatten a PDF
Filled-in forms, comments and signatures pressed into the page, on your own device, before you send it.
- Nothing is uploaded
- Works offline after first visit
- Open source
- No watermark · limit is your device’s memory; phones hold less
Flattens a filled-in PDF form, comments, stamps and signatures into the page so they cannot be edited, and keeps the text selectable. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after one visit to save itself for offline use, and then it works offline.
Done
Open the network tab. Your files never appear in it.
Add files and run the tool to see every request this tab makes.
Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.
How it works
- Drop one or more PDFs: a filled-in form, a marked-up draft, a signed contract.
- Choose Fields and annotations to keep the text selectable, or Whole pages as images for a copy with nothing left to edit.
- Press Flatten PDF and send the flattened copy. Keep your original if you might need to change an answer.
In your browser, not on a server
pdf-lib (MIT) reads the PDF in your tab. Fields filled in by an app that did not draw them get their appearance drawn first. Then each form field and annotation’s own appearance is placed into the page exactly where a reader shows it (scaled from its bounding box onto its rectangle, as the PDF specification describes) and the annotation is removed, along with the form. Links keep working, and sticky notes with no drawing of their own stay as notes. The image option instead renders each page with pdf.js (Apache-2.0) at 150 dpi, annotations included, and builds a new PDF from the pictures.
Compared with upload-based tools: Online flatteners upload the filled-in form, which is usually the most personal document you have: tax returns, applications, contracts, medical forms. Here it is flattened on your device, and text stays real text unless you ask for images.
Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
What does flattening a PDF do?
Form fields, comments, highlights, stamps, drawings and many electronic signatures sit on top of the page as separate layers that a PDF app can move, change or hide. Flattening draws each one into the page itself and removes the layer, so every reader shows exactly the same thing and the answers can no longer be typed over.
When do I need to flatten?
When the recipient must see exactly what you filled in. A form filled in one app can show empty boxes in another, and some court e-filing systems and application portals reject PDFs that still have fillable fields. Flattening before you print, merge or upload avoids both.
Is my PDF uploaded?
No. pdf-lib and pdf.js run in this tab, so tax forms, contracts and medical paperwork never leave your device.
Can I undo it?
Not in the flattened copy: the fields are gone and their answers are part of the page. Your original file is not changed, so keep it if you may need to edit the form again.
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Guides
- How to flatten a PDFA form you just filled in, or a document you just signed, stays editable until it is flattened. Here is what that means, and how to do it for free.