Security
What happens to your PDF
PDFMK is an online, server-processed tool. This page describes that flow without hiding it behind vague privacy claims.
Last updated: July 18, 2026
The short version
- You select a document in your browser.
- The browser sends it over HTTPS to the PDFMK API for the operation you requested.
- The API processes it in memory or in a short-lived temporary working directory.
- The result is returned to your browser for download.
- Temporary working files are removed when processing finishes or the request fails.
Uploaded document content is not used to create advertising profiles, train models, or build a permanent document library. PDFMK does not currently provide user accounts or cloud document storage.
Processing by tool
| Tool | Processing behavior | Result |
|---|---|---|
| Merge | Inputs are written to temporary PDF files so the merger can read them, then removed in cleanup. | One PDF |
| Split and preview | The uploaded PDF is read for thumbnail generation or page extraction; outputs are assembled in memory. | PDF or ZIP |
| Watermark | The document is read in memory, text is drawn on the requested pages, and a new PDF is returned. | One PDF |
| PDF to images | A temporary working directory holds source PDFs and rendered PNG files while the download archive is prepared. | ZIP of PNG files |
What you should not upload
No online processor can promise zero risk. Do not upload a document when law, contract, company policy, or professional duty requires it to stay on a managed device or an approved internal system. That can include medical records, identity documents, privileged legal material, export-controlled data, and unredacted financial records. Use an approved offline tool for those files.
Operational safeguards and limits
- HTTPS protects documents while they travel between a supported browser and the service.
- Temporary-path cleanup runs after successful and failed processing paths.
- ZIP inputs are inspected before extraction and non-PDF entries are ignored by the image converter.
- Password-protected or damaged PDFs may be rejected rather than partially processed.
- Practical size limits depend on page count, image complexity, selected DPI, and available server resources.
Read the Privacy Policy for information about technical logs, advertising, and data rights. Report a suspected vulnerability through the contact page.