Flatten PDF
Bake form fields and annotations into static page content so they can no longer be edited.
Flatten PDF online, free and private
Flattening a PDF merges its interactive layers — filled-in form fields, and optionally annotations like comments, stamps and links — into the static page content. After flattening, what you see is literally what the page is: nobody can click into a form field and change the value, drag a signature stamp, or delete a comment. It is the standard final step before sending a completed form, a signed agreement, or any document that must not be altered casually.
The whole process runs inside your browser. The PDF is opened locally with pdf-lib, form field appearances are baked into the pages on your device, and the flattened file is handed straight back — completed forms full of personal data never touch a server.
How to flatten pdf in your browser
- 1
Add your PDF
Click ‘Select PDF file’ or drop it onto the page. Fillable forms, annotated contracts and stamped drafts all work.
- 2
Choose what to flatten
‘Form fields only’ bakes filled values into the page while keeping links and comments interactive. ‘Forms + annotations’ also strips links, comments and stamps for a fully static document.
- 3
Flatten
Press the button and the interactive elements are converted to ordinary page content in one pass, entirely in your browser.
- 4
Download the static PDF
The result opens identically in every viewer, prints exactly as it looks, and its former form fields can no longer be edited.
Why use PDFToolz for this
Lock in completed forms
A filled form that isn't flattened is still editable — anyone can click a field and change the amount, the date or the name. Flattening converts each field's current value into fixed page content so the document you send is the document they keep.
Fix viewer compatibility problems
Form data and annotations render inconsistently across PDF viewers, and some browsers or print drivers drop them entirely — the classic ‘the form looks empty when I print it’ bug. Flattened content is plain page graphics, so it looks the same everywhere.
Choose how far to go
Sometimes you want links and comments to survive. The two modes let you flatten just the form fields, or sweep away every annotation for a completely static file ready for archiving.
Sensitive form data stays local
Completed forms are usually full of personal information — names, addresses, account details. Because flattening happens in client-side JavaScript, none of it is uploaded, logged or cached anywhere.