Security
What happens to your PDF
PDFMK processes common page operations locally and uses temporary server processing for compatibility and conversions.
Last updated: October 9, 2026
The short version
- You select a document in your browser.
- The document and image tools generate visual previews locally, without uploading the selected files.
- Merge, Split, Organize, supported image-to-PDF exports, and supported PDF-to-image exports run on your device. If local processing cannot finish, files automatically use temporary server processing. The processing dialog shows the switch and lets you cancel.
- When you start a server operation, the browser sends the document over HTTPS to the PDFMK API.
- The API uses a short-lived temporary working directory to process the request and prepare the result.
- The result is returned to your browser, and temporary working files are removed after the response 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 | Common PDFs are merged locally. PDFs with document-level features or large memory requirements automatically use the existing server merger when local processing cannot finish. | One PDF |
| Split | Selected pages and ranges are extracted locally into a PDF or ZIP. If local processing cannot finish, files automatically use temporary server processing. | PDF or ZIP |
| Organize | Page order, rotation, omission, and duplication are applied locally. If local processing cannot finish, files automatically use the existing server processor. | One PDF |
| Watermark | Only watermark text and appearance settings are sent to prepare a small asset. Your PDF is processed locally; compatibility failures automatically use temporary full-document server processing. | One PDF |
| PDF to Word | The first-page preview and text-layer check stay local. After you click Convert to Word, the selected PDF pages are processed in a temporary working directory and removed after the response. | One DOCX |
| PDF to images | Supported PDFs and ZIP inputs render locally using an engine downloaded on first conversion and cached by the browser. Engine, compatibility, or resource failures automatically use temporary server processing. | ZIP of PNG files |
| Images to PDF | Common images are placed on PDF pages locally, using the chosen layout and background. Unsupported decoders, CMYK JPEGs, animation, and resource limits automatically fall back to temporary server processing. | One PDF |
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.
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