Flatten PDF
A PDF flattening utility is a document locking tool that merges interactive PDF layers—such as form fields (AcroForms), digital signatures, and comments—directly into the static base content stream. By flattening these interactive elements, it prevents users from modifying text inputs or checking boxes in standard PDF viewers.
Flatten interactive forms, signatures, and annotations in your PDF files. Locks the values to make the document static and un-editable.
Quick Answer
Flatten a PDF file. Render interactive form fields, checkboxes, and text inputs into permanent, un-editable page graphics.
Drag and drop your files here, or browse
Supports .PDF files up to 20MB
Examples
Fillable form lock
Fillable fields → non-editable static PDF page
Signature locking
Interactive signature layers → flat image paths
How it works
This utility processes document structures using the pdf-lib assembly parser.
When an interactive PDF form is uploaded, the script loads the document tree into memory and retrieves the underlying form object via the pdfDoc.getForm() method.
The form fields, check states, signature visuals, and text inputs are merged into the document content streams by calling the form.flatten() method. This locks the visual representations onto each page's canvas layer and deletes the interactive form dictionary links, yielding a flattened document.
Irreversible Action: Once a PDF is flattened, the interactive fields cannot be turned back into fillable forms. Make sure to keep a backup of the original fillable file if needed.
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