ZasPDF: 100% Local and Private Processing
Professional PDF tools. Merge, split, and encrypt files directly on your device. Your privacy guaranteed with our Zero Cloud technology.
Merge
Combine multiple PDF files securely. Processing is 100% local on your device, ensuring total confidentiality for your corporate documents.
Split
Separate a large document or extract specific pages in seconds. Zero Cloud technology: your files are never uploaded to the internet.
Compress
Reduce the file size of your PDFs for easy sending. Premium and 100% local optimization, ideal for law firms and clinics.
Organize
Drag and drop to reorder the pages of your documents with a smooth and 100% private interface.
Rotate
Rotate the pages of your files quickly and securely right in your web browser.
Protect
Protect your sensitive documents with military-grade AES encryption. Being Zero Cloud, no one else has access to your original files.
Unlock
Remove the password from your own documents to edit or print them. The process takes place entirely in your browser.
Remove
Delete unnecessary sheets from your documents. Your files never leave your computer, giving you complete privacy.
IMG to PDF
Bundle your photos, invoices, or scans into a professional PDF document. Running locally keeps your information secure.
PDF to IMG
Convert entire documents to high-resolution images without relying on external servers.
PDF to Text
Extract text from your PDF files to plain text (.txt) instantly.
OCR PDF
Extract text from scanned PDF documents using Optical Character Recognition (OCR).
Edit
Add text, images, shapes or freehand annotations to a PDF.
Watermark
Add text or image watermarks to your PDF pages for branding and protection.
Number Pages
Add page numbers to your PDF document easily.
Crop
Trim margins or specific areas of your PDF pages easily and securely. 100% locally in your browser.
Grayscale
Convert your PDF to black and white. Perfect for saving printer ink.
Scan
Digitize documents and improve their perspective using your camera. All image processing occurs on your device.
Sign
Sign or stamp your documents securely.
PDF to Word
Convert your PDF files to editable Word documents locally. No upload, no cloud — your files stay on your device.
PDF to Excel
Extract tables and data from your PDF files into Excel spreadsheets. Runs entirely in your browser, no cloud.
PDF to PPT
Convert your PDF presentations to PowerPoint (.pptx) slides locally. Each page becomes a slide. No cloud required.
Word to PDF
Convert Word documents (.docx) to PDF format directly in your browser. 100% private, no files uploaded.
Excel to PDF
Convert Excel spreadsheets (.xlsx) to PDF documents locally. All processing happens in your browser.
PPT to PDF
Convert PowerPoint presentations (.pptx) to PDF files locally, right in your browser. No server upload needed.
How it actually works
"100% local" gets used a lot and means little without an explanation. This is what happens when you use any tool on this site:
1. The program travels to your browser, not the other way round
The first time you open a tool, the browser downloads the PDF engine (a library written in Go and compiled to WebAssembly, about 20 MB) and caches it. From then on it lives on your machine.
2. Your file is read into memory
When you pick a PDF, the browser loads it as bytes inside the tab and hands it to the engine. There is no upload: the Network tab of the developer tools shows no request carrying your file.
3. The result is produced and downloaded locally
The engine builds the new PDF in memory and the download link points at those bytes. Close the tab and nothing remains: not on disk, not on any server, not in a history.
Who this makes sense for
Not everyone. Local processing pays off when the file matters more than convenience:
Law firms and consultancies
Contracts under NDA, deeds, case files. Merge a contract with its annexes or password-protect it without it ever leaving the office.
Accounting and HR
Payslips, balance sheets, tax certificates. Split a payroll batch into one file per employee or pull tables into Excel without uploading third-party data anywhere.
Healthcare
Medical records, lab results, reports. Compress them for whichever channel the institution requires or remove pages that must not be shared.
Students and teachers
Scanned notes, assignments, theses. Scan with the phone camera, run OCR so the text becomes searchable and add page numbers before handing in.
What we deliberately don't do
Better to say it here than have you find out halfway through a task:
- There is no fallback server for huge files: your device's memory sets the ceiling. Several hundred megabytes can exhaust the tab, especially on mobile. The cloud alternatives page explains when a server-based service is the better choice.
- The signature is visual (drawn or uploaded as an image). It is not a certified digital signature with a trusted timestamp; that needs an e-signature platform.
- Conversions to Word, Excel or PowerPoint rebuild the content: they work well on simple documents and lose fidelity on complex layouts. Each tool page says so.
- No account is required for anything. An optional one exists (to sync preferences between the web and the mobile apps), and the site is funded by advertising, as the privacy policy explains.
Guides: how the PDF format works underneath
Long-form articles written by the team, with measurements taken using these same tools: what happens when you compress, why merging two PDFs is not concatenation, what a password really protects.
What actually happens when you compress a PDF (with real numbers)
We ran a text-only report and a scanned document through three real compression modes and measured the results. The setting that used to be our default made one of them fifty times larger — which is why it no longer is.
Why merging two PDFs is harder than it looks (and how to do it losslessly)
A PDF is not a stream of pages you can staple together. Here is what a merge tool actually has to do, why naive concatenation fails, and how to combine files without losing a single pixel.
Splitting a PDF: extraction, not division, and why the distinction matters
Two problems hide behind the word "split": pulling out a page range, and separating a bulk scan into the documents it contains. They are solved differently, and only one of them a tool can do for you.