Diff Doc vs Document Delta

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Document Delta compares two DOCX files and returns a document marked with Word's native tracked changes. Its web workflow is upload, compare, and download, with no signup required. The comparison covers paragraphs, tables, headers, footers, text boxes, content controls, and characters, detecting insertions, deletions, and formatting changes at run and character level. It can identify bold, italic, underline, font, and style changes even when the wording is unchanged. Reviewers can accept, reject, or comment on the revisions in Microsoft Word. The service also offers a REST API that compares two Word documents in one HTTP request without an SDK or API key, with examples for C#/.NET, Python, JavaScript, PowerShell, and Java. Files are processed in memory and discarded when comparison finishes. The free demo costs nothing. Each API file is limited to 500 KB, and the public API allows 10 requests per hour per IP address. The free comparison tool is in beta and actively improving.