Are my text and uploaded documents sent to any server?

No. The diff computation and document text extraction execute 100% client-side within your browser. Word (.docx, .doc) and plain text (.txt) files are read directly via the browser File API into memory. No file data or text is ever transmitted over the network.

How does document comparison work for Word (.docx, .doc) files?

For modern Word files (.docx), the browser extracts paragraphs, tables, and text runs from the underlying XML structure without altering content. For legacy Word files (.doc), an in-browser binary text stream scanner decodes text chunks directly into the editor for comparison.

Can I ignore minor formatting like spaces, tabs, or case differences?

Yes. You can toggle 'Ignore Case' to disregard uppercase and lowercase variations, and 'Ignore Whitespace' to eliminate false positives caused by differing indentation, trailing spaces, or line break styles (CRLF vs. LF).

Is there a limit on document size or character count?

There are no arbitrary software caps. The diff engine handles tens of thousands of lines smoothly in modern browsers. Extremely massive documents (over 100,000 lines) may take a few seconds to compute the Myers difference matrix.

Diff Checker — Compare Text, Word & TXT Documents | TopToolLab

/ Text tools — Diff Checker

Compare text & documents with instant precision

Spot line, word, and character differences across two text versions or uploaded Word (.docx, .doc) and text (.txt) files. Evaluated 100% in your browser without transmitting a single byte to an external server.

100% Client-Side Processing Supports .docx, .doc & .txt Split & Unified Views Zero Server Storage

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Step 01

Input or Upload Content

Paste text directly into the Original and Modified panels, or click Upload File to import Microsoft Word (.docx, .doc) or raw text (.txt) documents.

Step 02

Configure Diff Preferences

Choose your preferred display layout (Split Side-by-Side vs. Unified Inline), comparison resolution (words, lines, or chars), and ignore casing or spacing if needed.

Step 03

Review & Export Changes

Inspect highlighted additions in green and removals in red with exact line numbers. Export a unified .patch diff file or copy results directly.

/ 01 — Architecture & Capabilities

Built for precision document & text comparison

Unlike online services that send your confidential documents to unknown cloud backends, TopToolLab Diff Checker executes the Myers differential algorithm locally inside your web browser.

Direct Word & Text Extraction

Upload .docx, .doc, and .txt documents on either side. Modern Word documents are parsed via client-side XML DOM traversal, extracting paragraphs and tables cleanly into plain text.

Strict Air-Gapped Privacy

Compare legal agreements, proprietary source code, NDA drafts, or payroll notes with complete confidence. No files or text strings ever leave your device or touch a cloud server.

Dual Diff Engine & Patch Export

Toggle seamlessly between synchronized side-by-side split view and git-style unified inline view. Export standard unified diffs (.patch) ready for version control or developer handoff.

/ 02 — Questions & Answers

Frequently asked questions

Straight answers about how the diff algorithm processes files, handles formatting, and safeguards your confidentiality.

Is my text or uploaded Word document sent to any server?

No. Everything runs 100% inside your local browser tab. The text parsing, Word document reading, and difference computation use standard browser APIs (FileReader, WebAssembly, and local JavaScript).

You can verify this yourself by opening Chrome or Edge DevTools, switching to the Network tab, and clicking "Compare Difference" — no outbound HTTP requests will be created. The tool even continues working completely offline once the page has loaded.

How does the file upload feature extract text from .docx and .doc files?

For modern Microsoft Word .docx files, the browser opens the OpenXML package and parses the internal word/document.xml text stream via Mammoth.js, extracting paragraphs, line breaks, and table contents without requiring Microsoft Office.

For legacy binary .doc files (Word 97-2003), an in-browser binary stream scanner reads the document bytes to extract Unicode and ASCII text blocks directly into the input editor.

What is the difference between Split (Side-by-Side) and Unified views?

Split view aligns the original version on the left and the modified version on the right with twin line numbers. Unchanged lines stay parallel, making structural shifts, deletions, and additions immediately intuitive to the human eye.

Unified view collapses both files into a single continuous stream, placing deleted lines (highlighted in red with a - sign) directly above added lines (highlighted in green with a + sign). This format matches Git pull request diffs and standard patch files.

Can I ignore minor changes like trailing spaces or letter casing?

Yes. Use the Ignore Case checkbox to treat uppercase and lowercase characters as identical (e.g., "Apple" equals "apple").

Similarly, enable Ignore Whitespace to eliminate noisy diffs caused by differing tab indentation, Windows (CRLF) vs. Unix (LF) line breaks, or trailing spaces at the end of paragraphs.

What file formats and sizes are supported?

You can upload .txt, .docx, and legacy .doc files, or paste any text or code snippet (JSON, Markdown, Python, HTML, XML, CSV, etc.) directly into the text areas.

Because processing happens in memory, documents with tens of thousands of words are processed in fractions of a second. For massive files (over 50,000 lines), computation takes 1–3 seconds depending on your device's CPU.

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