Lock Fields — No Upload

Flatten PDF Forms Online — Make PDF Non-Editable

Permanently merge form fields into the page so no one can alter the values. Fill your form in Edge or Chrome, flatten it here, send with confidence.

100% private — your PDF never leaves your device.

Flattening runs locally in your browser using pdf-lib. No uploads, no account.

What does flattening a PDF do?

Interactive PDF forms contain editable fields — text boxes, checkboxes, radio buttons, and dropdowns — stored separately from the page content. Anyone who opens the PDF can change those values, even after you have filled them in.

Flattening merges the filled values permanently into the static page layer and removes the field structure entirely. The result looks identical but is no longer editable — the values are baked in as regular page content, just like a scanned document.

Recipients cannot edit values

Once flattened, text boxes and checkboxes become static pixels. No recipient can alter your numbers, name, or selections.

Fields merged, not deleted

The filled values stay visible on the page. Flattening removes the editable layer — your data is preserved as page content.

Works on any filled PDF

Flatten tax returns, contracts, applications, or insurance forms filled in Edge, Chrome, Acrobat, or Preview.

When to flatten a PDF

Tax returns

Fill your W-2, 1040, or state return in your browser, then flatten before emailing to your accountant. They see the numbers; they cannot change them.

Contracts and agreements

After filling in your name, date, and agreed terms, flatten the contract before countersigning. The other party gets a document with locked values.

Job applications

HR application forms often arrive as fillable PDFs. Flatten after completing so your details cannot be altered before the hiring team reviews them.

Insurance and benefits forms

Medical, dental, and life insurance forms contain sensitive choices. Flatten before submission to prevent accidental or deliberate edits by processors.

Government documents

Permit applications, visa forms, and government filings should be submitted with locked fields. Flatten to ensure the document arrives exactly as you completed it.

Archiving filled forms

Flattened PDFs are smaller, render faster, and are more compatible with older viewers. Archive completed forms as flat PDFs for clean long-term storage.