Is my PDF uploaded to flatten it?

No. Flattening happens in your browser — the file never leaves your device. Smallpdf and PDF24 upload your PDF to flatten it; AttachKit doesn't.

What does flattening a PDF do?

It draws each interactive form field's current value into the page and removes the editable field, so the answers are baked in — visible in every reader and no longer changeable.

What if my PDF has no form fields?

Flattening only applies to interactive form fields. If a PDF has none, there's nothing to flatten — a PDF without a form is already 'flat'. Flattening is specifically for locking in the answers on a filled-in form.

Yes — unlimited, no account, no watermark.

Flatten a PDF

Bake a filled form's values into the page so it can't be edited or re-filled — the standard way to make a PDF uneditable before you send it. It all runs in your browser; nothing is uploaded.

100% local. The PDF never leaves this device — open DevTools and watch.
Locks in answers. Form fields become part of the page — viewable everywhere, editable nowhere.

Drop a PDF here

or tap to choose a file

Flatten a PDF so it can't be edited

Bake a filled form's values into the page so they can't be changed — entirely on your device, with no upload.

Nothing is uploaded

The whole thing runs in your browser — open your network tab and watch: your file never leaves your device. Most online tools round-trip your document through their servers.

Locks in the answers

Form fields become part of the page content, so the values show in every PDF reader and can no longer be edited or re-filled.

Free, no account

No watermark, no sign-up. Flatten the form and download it.