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Crowdsourced Redlines

redlines.opensource.legal

Free plan WebAPISelf-hosted
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Spec score 7.9 #14 of 25 in Document Comparison Software

What it is

Crowdsourced Redlines compares two Microsoft Word.docx files and creates a third document with insertions, deletions, and moved text marked as native Word tracked changes. Reviewers can accept or reject each change individually in Word. The comparison engine also detects formatting changes and handles tables. In the browser, the comparison runs locally through WebAssembly in a Web Worker, and the result downloads to the device; this default workflow does not send files to a server. An optional server-side API processes documents in memory and stores nothing. The engine is described as a.NET 8 WebAssembly modernization of Microsoft’s archived Open-Xml-PowerTools comparison engine. The comparison engine, document viewer, Python wrapper, and web app are MIT-licensed and publicly developed on GitHub. Developers can use packages for TypeScript or JavaScript, Python, and C#/.NET. The codebase can be self-hosted, audited, or embedded. Users can report poor comparisons by filing a public ticket with source files, which then becomes a regression-test fixture. The free tool is listed at free.

Spec sheet

Purpose
Crowdsourced Redlines compares two Microsoft Word .docx files and produces a third document with insertions, deletions, and moves as native Word tracked changes.Read 7 Oct 2026 · redlines.opensource.legal
License
The site says the comparison engine, document viewer, Python wrapper, and web app are MIT-licensed and publicly developed on GitHub.Read 7 Oct 2026 · redlines.opensource.legal
API privacy
The optional server-side API processes documents in memory and stores nothing.Read 7 Oct 2026 · redlines.opensource.legal
Browser processing
The browser app runs its comparison locally via WebAssembly in a Web Worker, and the result downloads directly to the device.Read 7 Oct 2026 · redlines.opensource.legal
Comparison engine
Docxodus is described as a .NET 8 WebAssembly modernization of Microsoft's archived Open-Xml-PowerTools comparison engine.Read 7 Oct 2026 · redlines.opensource.legal
Comparison features
The comparison engine adds move detection, format-change detection, and improved table handling.Read 7 Oct 2026 · redlines.opensource.legal
Crowdsourced feedback
Users can file a public ticket with source files when a comparison produces a bad redline; the ticket becomes a regression-test fixture.Read 7 Oct 2026 · redlines.opensource.legal
Developer packages
The engine is available for TypeScript or JavaScript, Python, and C#/.NET.Read 7 Oct 2026 · redlines.opensource.legal
File privacy
The default browser comparison does not upload files to a server.Read 7 Oct 2026 · redlines.opensource.legal
Output
Reviewers can accept or reject each tracked change individually in Word.Read 7 Oct 2026 · redlines.opensource.legal
Self-hosting
The site says users can self-host, audit, or embed the open-source codebase.Read 7 Oct 2026 · redlines.opensource.legal
Supported documents
The described web tool compares Microsoft Word .docx files.Read 7 Oct 2026 · redlines.opensource.legal

Plans and prices

Free Free Free, open-source DOCX comparison tool Read 7 Oct 2026 · redlines.opensource.legal

Every Crowdsourced Redlines plan and price →

Strong points and limits

Strong points

  • Creates native Word tracked changes
  • Browser comparisons run locally by default
  • Optional API stores no documents
  • Supports move and formatting-change detection
  • Open-source code can be self-hosted or embedded

Limits

  • The described web tool compares .docx files
  • API comparisons are server-side
  • Poor-result reports with source files become public tickets

Who it suits

It suits people reviewing Word documents who want changes presented as native tracked edits. Developers and organizations needing API or self-hosting options can also use the available packages and codebase.

Verdict

Crowdsourced Redlines offers a focused way to compare Word documents, with local browser processing as the default and optional API and self-hosting routes. Its document scope is .docx comparison.

Where Specifiction places it

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