Browser-side processing
Many operations such as PDF merging, image resizing, workbook cleanup and document generation can be performed in the browser. For those workflows, the selected source file does not need to be intentionally uploaded to FileFiddler servers.
Browser-side processing also means performance can depend on your device, available memory, browser and file size.
Protected reconstruction tools
Some problems require distinctive reconstruction logic. PDF to Excel can send extracted text and page coordinates to the protected FileFiddler service. Image to Excel performs OCR in the browser and can send recognized text boxes and lightweight geometry for reconstruction. Split PDF by Category can send extracted page text for category analysis.
The relevant tool page and Privacy Policy describe the processing model for each workflow. FileFiddler does not claim that every tool is local-only.
How tools are tested
Tools are checked with representative files and edge cases before they are listed as live. Conversion tools are reviewed for both successful output and common failure modes such as unusual page layouts, OCR mistakes, merged spreadsheet cells and unsupported source structures.
No converter can guarantee perfect output for every possible file. File formats, fonts, scans and source quality vary widely, so important results should be reviewed before they are relied upon.
Why the site documents limitations
A useful tool should explain when it works well and when it may need manual correction. FileFiddler therefore documents source requirements, known limitations and privacy behavior beside the tools rather than presenting every conversion as perfect.
If a tool behaves unexpectedly, support@filefiddler.com can be used for a bug report. Do not send confidential source files unless they are necessary and you are authorized to share them.