.NET API to Compare & Merge Documents

Develop .NET Applications using Documents Comparison API to Compare & Check for Difference in Content & Style Among Same Format Documents.

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.NET document comparison API

GroupDocs.Comparison for .NET


GroupDocs.Comparison for .NET API is a fast and reliable solution to build difference checker applications among documents of same format in C#, ASP.NET or other .NET related technologies. The .NET compare library supports checking differences in both, content as well as the text style of popular image and document formats such as PDF, HTML, Outlook email, Microsoft Office Word documents, Excel spreadsheets, PowerPoint presentations, OneNote, Visio diagrams, text and images. The comparison can be done to detect content changes for words, paragraphs and characters while providing a comparison document that lists summary of differences. GroupDocs.Comparison for .NET API can easily extract basic information of source document. It can also fetch, compare and save simple, password enables, as well as encrypted documents via file or stream.

GroupDocs.Comparison for .NET can be used to develop applications in any development environment that targets .NET platform. It is compatible with all .NET based languages and supports popular operating systems (Windows, Linux, MacOS) where Mono or .NET frameworks (including .NET Core) can be installed.

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GroupDocs.Comparison for .NET Features



Identify Differences in Content and Font Styles


Save a Summarized List of All Differences Found after File Comparison


Apply or Reject Changes after Analyzing Differences and Export Resulting File


Support for Microsoft Word “Track Changes” Functionality while Comparing Word Files


Uniquely Spot Changes Coming from Each Document being Compared


Read and Send Documents via Streams


Metered Licensing – Billing According to API Usage


Compare Multiple Source Documents with a Single Target Document


Compare Specific Pages of Word Files with each other


Merge up to 3 Word Documents and Compare Formulae used in Word Files


Get Information about Documents from filePath


Save HTML Comparison Result as Images


Option to Show or Hide Deleted Content


Option to Turn Style Comparison of Documents ON or OFF


Specify Strings to Mark Inserted, Deleted & Style Change Items in Comparison Document


Specify Word Separator & Font Color to Stylize Compared Text


Calculate Correct Coordinates of Changes in PDF, Word, PowerPoint Slides & Diagrams


Compare Password Protected Files


Compare Chart Titles in Spreadsheets


Autosize the auto-shapes in resulted file of Cells document


Chart generation in the resulted Cells Files

Easily Compare Documents using .NET API

GroupDocs.Comparison for .NET API provides you an easy and efficient way to compare your files. Following is an example that shows, how to compare two DOCX documents using C#:

Easily Compare Documents using C#

 //Source and target files to be compared
string source = @"source.docx";
string target = @"target.docx";
Comparer comparer = new Comparer();
//Compare two documents
ICompareResult result = comparer.Compare(source, target, new ComparisonSettings());

Choose Detail Level for Comparison

With GroupDocs.Comparison for .NET you can specify the extent to which you want the documents to be compared. You can choose among, low (compare text word by word with accuracy for imaging grid = 50), middle (compare text character by character with accuracy for imaging grid = 100) or high (compare text character by character with accuracy for imaging grid = 150).

Support for Text Style Comparison

GroupDocs.Comparison for .NET offers feature to compare text style.

While words and characters of documents are being compared, the font name, font size, font color, font style (Bold, Italic, Underline, Small Caps, Hyperlink) and underline color (if applicable) can be compared to find differences.

While comparing paragraphs, you can compare styles such as, paragraph alignment, indentation (left indent, right indent), paragraph spacing (space after, space before), first line indent, and line spacing.

GroupDocs.Comparison for .NET also supports comparing other sections of a page, where applicable, such as footer distance, page height & orientation, margins (left, right, top, and bottom), border line width, and border color.

Support and Learning Resources


GroupDocs.Comparison offers document automation APIs for other popular development environments as listed below: