Skip to content
Vault Studio Pro
Menu

PDF

A PDF editor that works in your browser, without uploads

Annotate, sign, fill in forms, redact, OCR, merge and split PDFs in Vault Studio Pro. The PDF engine runs in your browser tab, so contracts, statements and scans never pass through someone else's server.

Open the PDF editorHow the privacy works

What the PDF editor does

Most free PDF websites work by uploading your file, processing it on their servers and sending it back. Vault Studio Pro does the same jobs with the PDF libraries loaded into your browser: pdf.js to display pages, pdf-lib to write changes, and Tesseract for text recognition. These libraries and their data files are served from our own site, and the page's security policy stops it from contacting anyone else.

How to edit a PDF

  1. Open the app, choose PDF, and open a file or drop it onto the window.
  2. Pick a tool from the toolbar (highlight, text, signature, redact and so on) and click on the page.
  3. Save the edited PDF back to your computer.

Annotate and sign

  • Highlight, freehand drawing, lines, arrows, text boxes, rectangles and circles.
  • Sticky notes, saved as real PDF comments that other PDF readers show.
  • Signatures you draw, type in a script font, or upload as an image, with an optional name, date and title. These are visual signatures, not certificate-based digital signatures.

Fill in forms

Existing form fields (text, tick boxes, radio buttons and drop-downs) can be filled in, and you can add your own text fields and tick boxes to a PDF that has none. Save it as an editable form, or flatten it so the answers become part of the page.

Redact

Redaction burns black boxes into the page so the text underneath is really gone, not just covered. See how PDF redaction works for the details and trade-offs.

OCR: make scans searchable

Scanned pages are just pictures of text. OCR (optical character recognition) reads them so you can search, copy or send the text to Docs, and tables to Sheets. Pages that already contain real text are read directly, without OCR. OCR currently recognises English. On the free plan it runs on the first page of each PDF. Pro runs it on every page and adds "OCR all".

PDF Tools: merge, split, compress and more

  • Organise pages: rotate, reorder, duplicate and delete.
  • Merge several PDFs, and images, into one PDF.
  • Split a PDF into parts.
  • Add a text watermark.
  • Compress, which re-encodes images. Pages that are mostly text won't shrink much.
  • Protect, which locks the PDF inside a password-protected .vault file. This is not a standard PDF password.
  • Convert a PDF into an editable .docx.

Jobs with up to 3 files are free. Larger batches need Pro. See pricing.

Limits worth knowing

  • It is not a full layout editor: you add content on top of pages rather than reflowing the original text. To rewrite a document, convert it to .docx first.
  • For password-protected PDFs, page operations are disabled, and saving produces a copy made of page images.
  • Very large PDFs are limited by your device's memory, because everything happens on your device.

Common questions

How accurate is the OCR?

It uses Tesseract, a widely used open-source OCR engine. It works best on clean, straight scans of printed English text at a good resolution. Handwriting, low-contrast photos and unusual fonts produce more mistakes, so proofread anything important.

Is a signature added here legally binding?

The signature is an image placed on the page, much like signing a printout and scanning it. Whether that's acceptable depends on the document and on who you're sending it to. It is not a certificate-based digital signature.