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Security & Privacy

Flatten PDF Online, Free

Flatten a PDF online free so what you see is all there is: form answers, comments, stamps and drawn signatures become part of the page and can’t be changed or deleted. Nothing is uploaded.

Settings appear once you add a PDF.

Form fields Answers become plain page content that can’t be changed.
Comments, highlights, stamps and drawings
Advanced 3
Keep clickable links
Remove scripts and automatic actions
How flat

Done on your device No upload, no queue, no sign-up.

Bytes sent anywhere: 0 B

How to flatten a PDF online free

Your PDF goes into this browser tab, is flattened on your device, and comes back as a PDF nobody can edit. 0 bytes uploaded

  1. Add your PDFs

    Drop the filled form or commented PDF.

  2. Check the settings

    Choose what to flatten: form fields, comments and stamps, and whether to strip scripts.

  3. Save the result

    Save it. Every viewer now shows exactly the same page, and nobody can edit the answers.

Why it doesn’t upload

The PDFs people flatten are filled-in forms and signed agreements — names, addresses, ID numbers, signatures. Flattening them here keeps that data on your device instead of passing it through a stranger’s server on the way to being locked.

Check it in your browser’s Network tab

Worth knowing

  • Flattening can’t be undone in the new file. Keep the original if you might need to change an answer.
  • Links survive by default; untick Keep clickable links to flatten them too.
  • Comments without a visible appearance (some sticky notes) are removed rather than drawn.
  • “Pages to images” makes the file larger and its text unselectable — use it only when you need nothing to be extractable.

Under the hood

What happens to your file

Form fields have their current appearance drawn into the page and are then removed, so the answers can no longer be changed. Comments, highlights and stamps are drawn in from their appearance streams (ISO 32000 §12.5.5) and removed; scripts and automatic actions are deleted. The stronger setting rebuilds each page as an image, leaving nothing editable at all.

Runs on pdf-libpdf.js

Reference: ISO 32000-2 (PDF 2.0)

Questions

What does it mean to flatten a PDF?

It merges everything layered on top of the page — form fields, comments, stamps, signatures — into the page itself. The PDF looks the same, but those items can no longer be edited, moved or deleted.

How do I make a fillable PDF non-editable?

Fill it in, then flatten it here with Form fields switched on. The answers become ordinary page content, so nobody can change them before printing or forwarding.

Is flattening the same as redacting?

No. Flattening keeps everything visible and makes it permanent. Redacting removes content. To hide something, use Redact PDF instead.

Why do forms look different in different PDF readers?

Each reader draws unflattened fields itself, with its own fonts and rules. Flattening fixes the appearance once, so Chrome, Preview and Acrobat all show the same thing.

Will the text still be searchable?

Yes, in the default mode. Only Pages to images under Advanced turns pages into pictures.

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