PDF24 Compare PDF vs PDFOptim

PDF24 Compare PDF compares two versions of a PDF and marks text that has changed, been added, or been removed. Readers can view the documents side by side, as an overlay, or with a slider. The comparison runs directly in a browser without installation, and PDF24 says the files are not uploaded to its servers. Google Drive is listed as a file-selection option. Use is free, with no registration or time restrictions. PDF24 says transfers are SSL secured and server files are automatically deleted after one hour. For offline processing, PDF24 Creator keeps files on the local PC, but it can only be installed on Windows; Linux and Mac are not supported. PDF24 Tools can be installed from a browser on Android or iPhone and iPad, though it is not distributed through Google Play or the App Store. PDF24 says its online tools are available to companies free of charge and without restriction, and a data-processing agreement can be requested.

PDFOptim provides browser tools to compress, merge, split, rotate, and reorder PDF files, alongside native apps for macOS, iOS, iPad, and Windows. Browser processing uses JavaScript and WebAssembly without uploading files to PDFOptim servers, and the tools work offline after the page has loaded; initial loading and license verification need internet access. Compression offers Web, Standard, Print, and Custom settings, and can reduce PDF size by up to 90%. Compress Only mode strips metadata and compresses internal streams without re-rendering software-created PDFs, preserving selectable text. Multiple PDFs can be batch-compressed, while downloading all results as a ZIP requires Pro. The free plan allows three operations per day on files up to 25 MB. Pro Monthly costs $4.99 a month and includes unlimited operations, files up to 200 MB, and batch ZIP downloads. Lifetime costs $19, paid once, with the same operation and file limits, batch ZIP downloads, future tools, and priority email support. The native apps process documents locally; a 30-day money-back guarantee is also listed.