Flatten PDF

Runs in browser PDF Security & Privacy

Turns interactive form fields into fixed text and graphics that cannot be edited, and can strip comments, stamps and links. The result prints and displays identically everywhere.

Privacy: Processed locally in your browser. Your file is not uploaded.

How do PDF passwords, permissions and redaction work?

PDF encryption (ISO 32000, AES-256 in current files) has two passwords: the user password opens the document, the owner password controls permissions such as printing, copying and editing. Permissions are advisory flags that compliant readers honour, not a cryptographic barrier. Redaction is different from covering: a black box drawn over text leaves the text in the file, whereas true redaction removes it from the content stream — and metadata, attachments and thumbnails can leak what the pages no longer show.

Security note: Before sharing a redacted or "cleaned" PDF, inspect its metadata and text layer: what a viewer cannot see may still be in the file. Permissions stop honest readers, not determined ones.

Read the guide: How to Edit a PDF Without Uploading It

How to use Flatten PDF

  1. Drop a PDF.
  2. Keep "Flatten form fields" on; tick "Remove annotations" if wanted.
  3. Click "Flatten".
  4. Download.

Flatten PDF features

  • Burns form field values into the page
  • Optional removal of all annotations
  • Reports fields flattened and annotations removed
  • Unchanged output when there is nothing to flatten
  • Password-protected input supported
  • Local processing

Flatten PDF example

Lock a filled application form

Input:

application-filled.pdf — 24 fields

Output:

application-flattened.pdf — 24 fields flattened, values visible everywhere, no longer editable

Frequently asked questions about Flatten PDF

What does flattening do to a form?

Each field’s appearance (the text you typed, the ticked box) is drawn into the page and the field itself is removed, so the values can no longer be changed and are visible in every reader.

Are comments and highlights flattened too?

Annotations cannot be burnt into the page by this engine; tick "Remove annotations" to strip them, or leave them as they are.

Can I un-flatten later?

No — flattening is one-way. Keep the original form if you may need to edit it again.

Is my PDF uploaded to a server?

No. The file is opened and processed by your browser with WebAssembly and JavaScript; nothing is sent to Mutqan Soft or anyone else. Close the tab and the file is gone. Downloading the result needs a free account — no subscription, no payment.

Can I use it on a password-protected PDF?

Yes, if you know the password: the file list asks for it once and every operation then works on the decrypted pages. The output is saved without a password unless you protect it again.

Technical notes

pdf-lib’s form.flatten() draws each widget’s appearance stream into the page content and removes the field and widget objects. Annotation appearance streams of other types are not merged into the page by this engine; the option removes them instead.

References