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Local PDF tool - browser processing

Sign a PDF without uploading

Signing a PDF without uploading means adding a visual signature to the page locally, with the file never leaving your device. You draw, type, or import a signature, place it where it belongs, and export the signed PDF — all in your browser.

Sign locally See the proof

0 bytes sent proof

What the widget measures

The panel counts what leaves your browser after you choose a file. The site's own scripts and fonts load like any web page — what you will never see is a request carrying your PDF. Check it here, or open your browser's Network tab and see for yourself.

0 bytes of your document sentStarts measuring when you choose a file on a tool page
Document request bodies
0 bytes
App network after file open
0 bytes
Processing engine
Browser WASM worker

The number is scoped to request bodies after you choose a document. App assets such as JavaScript, WASM, and fonts can still load; those are not your PDF bytes.

Verify it yourself
  1. Open DevTools, then the Network tab.
  2. Choose a PDF in the tool and complete the action.
  3. Filter for fetch or XHR requests; document processing should not create a request carrying your file.

Stronger check: load the tool page first, then disconnect from the network before choosing the file. Already-loaded tool code can continue processing locally, but a first visit still needs the site assets.

Local vs. online

How local processing compares

Doing this in Lemmafour keeps the file on your device. A typical online PDF tool uploads it to a server first — here is the practical difference:

  Typical online PDF tool Lemmafour
Where your file goes Uploaded to the provider’s servers Stays in your browser — never uploaded
Works offline No — it needs a round trip to their server Yes, once the page has loaded
Account or sign-up Often required Never — no account, no email
What they keep afterwards Your file sits on their servers until they delete it Nothing to keep — it never left your device

Steps

How to do it in Lemmafour

  1. Choose Sign locally.
  2. Open the PDF from this device.
  3. Create a drawn, typed, or imported signature in Signature Studio.
  4. Place the signature, initials, date, checkmark, or text where needed.
  5. Apply signatures and export the PDF.

Expert note

Signature validity

A visual signature is page content. It can be appropriate for many informal workflows, but it is not the same as a certificate-based digital signature with identity proofing and tamper evidence. For regulated filings, court documents, or contracts with strict signing requirements, confirm the required method. This is not legal advice.

FAQ

Questions people ask before using this tool

Can I draw my signature?

Yes. Signature Studio supports drawn signatures along with typed and imported signature images.

Are saved signatures stored online?

No. Optional saved signatures stay in this browser profile and can be forgotten.

Does the PDF leave my device?

No. Signing happens in your browser. Click the "Local · 0 sent" button — or open your browser’s Network tab — and watch for yourself.

Related private PDF workflows

Keep working locally

Sign an NDA on your phone without uploading Open an NDA in Lemmafour, place a visual signature, and export it locally from a mobile browser. Fill and sign a PDF contract without uploading Fill contract fields and add a visual signature locally in your browser with Lemmafour. Add an image to a PDF without uploading Place a local image into a PDF in your browser. The PDF and image stay on this device. Stamp a confidential PDF without uploading Add approval, draft, confidential, void, or sign-here stamps to a PDF locally in your browser. PDF tool hub Browse the shipped local PDF tools.