How the technology works
Just PDF Tools reads selected files in your browser, creates the output on your device and offers a local download. There is no document-upload endpoint.
From selection to download
The browser File API reads the files you choose into memory. pdf-lib copies PDF pages or embeds JPG/PNG images. JSZip packages separately extracted pages into a ZIP. A local object URL makes the result downloadable; file contents are not sent to our server.
Quality and orientation
PDF pages are copied rather than rendered as screenshots. JPEG image bytes are embedded without recompression. Image aspect ratios are preserved. Our code reads JPEG/PNG EXIF orientation and applies the corresponding rotation or reflection, including all eight orientation values.
Boundaries and tests
Tasks allow up to 50 files and 100 MB total. Splitting is limited to documents of 1,000 pages. Memory use can exceed source file sizes. Automated tests cover merging, ranges, ZIP output, page sizes and EXIF transforms. Password-protected files are unsupported. Forms, bookmarks, attachments and digital signatures may not survive.
What local processing does not mean
The website still needs to load from its host. Local processing is not an independent security audit, a guarantee about your browser or a promise of secure deletion. Keep originals and inspect downloads. There is no OCR, redaction or signature-preservation feature.