Most online PDF sites work by uploading your file to their server, processing it there, and letting you download the result. This editor does not have a server for your files: the OnlyOffice PDF engine is compiled to WebAssembly and runs inside your browser tab. When you pick a file it is read straight from disk into memory — there is no upload step and no server round-trip — so confidential PDFs stay on your machine.
You can scroll, zoom and search the document, add comments and free-text annotations on top of the page, and save it back as a PDF that keeps those annotations. Because PDF is a fixed-layout format the body text is not rewritten like a Word document; if you need to change the wording, open the original DOCX, XLSX or PPTX here and export a fresh PDF from it — also on your device.
How it works
- Click Open your PDF to launch the editor in your browser.
- Pick a .pdf file from your device, or drag and drop it onto the page.
- It renders locally with the OnlyOffice PDF engine — read it, search it, add comments and annotations.
- Download it again as PDF when you are done; your annotations are merged into the file locally.
What you can do
- Open and read any .pdf file — text, scans, forms, multi-page reports
- Add comments and free-text annotations, then save back as PDF
- Create a PDF from a DOCX, XLSX or PPTX with Download as PDF
- No Adobe Acrobat, no Reader, no account, no Copilot
- No upload — your PDF never leaves your device
- Works offline as an installable app
Frequently asked questions
Can I open a PDF without Adobe Acrobat?
Yes. It opens PDF directly in your browser with the OnlyOffice PDF engine — no Acrobat, Reader or account.
Is my PDF uploaded anywhere?
No. The file is read into the browser tab and rendered locally with WebAssembly. It never leaves your device.
Can I annotate the PDF, not just read it?
Yes. Add comments and free-text annotations, then save back as a PDF that keeps them.
Can I rewrite the text of an existing PDF like a Word document?
Not as free-flowing text — PDF is fixed-layout. Read, comment and annotate here; to change wording, open the original DOCX/XLSX and export a new PDF from it.
Can I create a PDF from a Word or Excel file here?
Yes. Open the DOCX, XLSX or PPTX and choose Download as PDF — the PDF is generated on your device.
Does it work offline?
Yes. After the first visit the editor is cached as an installable web app and opens PDFs without a connection.
Is there a file size limit?
No fixed limit. Everything runs in your browser, so the practical ceiling is your device's memory.