Diff Master – Local File Compare

Compare PDFs, spreadsheets, text, code, JSON and Markdown locally in Chrome. No uploads. No account required.

Diff Master opens a focused Chrome side panel for comparing PDF, Excel and CSV files, text, code, JSON, and Markdown locally in your browser. Data handling Your comparison files and text are processed locally in the side panel. Diff Master does not upload or store your comparison content. The extension does not read the websites you visit, collect browsing history, or use analytics. Website, privacy, terms, and support pages open only after you choose their links. No account is required. Core comparison code, workers, and supporting resources are included in the extension package. Compare six types of content • PDF — Compare extractable text or rendered page appearance. Review changed pages in Overlay, Side by side, or Stacked view. Each file can be up to 50 MB and 150 pages. • Excel, XLS, and CSV — Select one sheet from each file, align columns and rows, compare saved values, types, and formula text, filter results, and download a local CSV change report. • Text — Review line-level changes with word-level detail. • Code — Compare source text with language-aware highlighting and a unified diff. Code is never executed. • JSON — Compare strict JSON structure and values. Object key order is ignored and array order is preserved. • Markdown — Compare source and structural changes, with a safe rendered preview. Important boundaries PDF text comparison does not verify layout or legal meaning. PDF visual comparison does not verify wording or legal meaning. Spreadsheet formulas are not recalculated, and macros, charts, formatting, external connections, and workbook editing are not supported. Diff results are a review aid; check important changes independently. Privacy and permissions Diff Master requests only Chrome’s Side Panel permission. It does not request host permissions, activeTab, tabs, scripting, storage, or content-script access. Inputs and results remain in the current side panel memory session and are cleared when that session is discarded. For guides, privacy information, and support, visit the official Diff Master website. Do not send comparison files, passwords, API keys, access tokens, or other sensitive comparison content by support email.