- 1Upload
- 2Process
- 3Download
Certificate Sign PDF online, free
Digitally sign a PDF with a PKCS#12 certificate (PAdES), with timestamping and long-term validation.
- Runs in your browser — no upload
- Free, no sign-up, no watermark
How to use Certificate Sign PDF
- 1
Add your PDF files
Drop one or more files on the page, paste it, or click Select Files. Nothing is uploaded — it opens straight in your browser.
- 2
Fine-tune the settings
The defaults already suit most files; change them only if you need to.
- 3
Run Certificate Sign PDF
Press the start button. Processing happens on your device, usually in seconds.
- 4
Download the result
Save the finished file, or continue with another tool without downloading in between.
What Certificate Sign PDF can do
- Private by design — files are processed in your browser and never uploaded
- Batch processing — up to 2 files at once
- Free with no sign-up, no watermark and no daily limit
Certificate Sign PDF — frequently asked questions
Is Certificate Sign PDF really free?
Yes. Certificate Sign PDF is free forever on Sada Files — no ads, no premium tier, no watermark, no daily cap that pushes you to pay. Every option on this page is available to everyone.
Do I need to sign up or create an account?
No. There is no account system at Sada Files. Open the page, drop your file, pick your options and save the result. History and saved workflows stay on your device.
Is my file uploaded anywhere?
No. Certificate Sign PDF runs on your device — in your browser using WebAssembly, or inside the free native app. Your file never leaves your computer or phone, which is why there is no upload wait.
Which formats does Certificate Sign PDF accept?
Certificate Sign PDF accepts PDF. Files are identified by their content, not their extension, so a mislabelled file still works.
Is there a file size or file count limit?
Only what your device can handle. Because processing happens locally there is no server cap, no queue and no "upgrade for larger files" message. Batch as many files as you like.
Can I chain Certificate Sign PDF with other tools?
Yes. After every result a Continue with… menu lists every tool that accepts this output, and the file is handed over in memory. Save the chain as a workflow and re-run it on hundreds of files, or call it in one API request.
Does Certificate Sign PDF work on my phone?
Yes. The web app works on Android and iOS browsers, and the free Sada Files app for Android, iOS, Windows, Linux and macOS runs Certificate Sign PDF fully offline.
Related tools
- Verify PDF SignatureValidate digital signatures — certificate chain, signer, timestamp and whether the document changed after signing.
- Sign PDFDraw, type or upload your signature and initials, add a date and place them anywhere — reusable signatures are saved on your device.
- Protect PDFEncrypt a PDF with an open password and an owner password — AES-128 or AES-256 — and set print, copy, edit and annotate permissions.
- Redact PDFPermanently remove text and images — draw boxes, or search by text or regex for emails, phone numbers and IDs.
- Remove PDF MetadataStrip XMP, the info dictionary and hidden data from a PDF before sharing.
- Unlock PDFRemove a password you know, or lift owner-only restrictions on printing and copying.