Aspose.Words or NPOI

Sometimes we get the following question: why should we use Aspose products rather than the NPOI? This question is easy to answer: features and functionality.

NPOI (NET version of POI Java project) is an open source project that can help you read or write files in Microsoft Office formats. As part of the current comparison, consider the following NPOI components – HWPF and XWPF:

  • HWPF provides reading and writing of Microsoft Word 97 file formats and limited support for reading Word 6 and Word 95 file formats

  • XWPF provides reading and writing of Word 2007 file formats

Both HWPF and XWPF provides Basis Text Extraction, Specific Text Extraction, Access of Header & Footers, and Changing Text features. While HWPF and XWPF provide similar functionality, they currently do not have a common interface. It has a fairly stable core API providing read or write access to the main parts of .DOCX files, but it is not complete.

Aspose.Words is a very useful document processing library that provides great support for all Microsoft Word and other document formats. With Aspose.Words you can view, generate, modify, convert, render, and print documents without using Microsoft Word.

In this article, we will look at when it makes sense for you to prefer Aspose.Words.

Why not NPOI

It is worth noting that some tasks can be achieved with Aspose.Words, but cannot be accomplished with NPOI. For example, if you need to perform a mail merge operation and then modify the result document, then you cannot use only NPOI, you also need Microsoft Word. The point is that the merge results are not directly stored in a .DOCX file, and NPOI can only receive data that was stored in the .DOCX file. That is, you will need to complete the mail merge in Word, save the result to a .DOCX file, and then modify this file.

You can compare NPOI with Aspose. To do this, we suggest that you familiarize yourself with the Aspose.Words for NPOI project (HWPF and XWPF) – it shows how different tasks can be done using the Aspose.Words for .NET API versus NPOI. The project also covers features for working with text documents that are only available in Aspose.Words, but not in NPOI.

This project is also useful for developers looking to migrate from NPOI to Aspose.Words.

In the following sections and articles, we will take a closer look at some of the features and abilities provided by Aspose.Words.


Aspose components are thoroughly tested. Since Aspose components are packaged into a single DLL, there will never be a need to install any additional parts or pieces for them to function. This allows not only to provide a stable work with Aspose.Words, but also reduce the risk of unforeseen situations to virtually zero.

Scalability and Speed

Aspose components are highly scalable and lightning fast. They are a true .NET solution and perform flawlessly on either a single server powering a single application or a load balanced web farm powering an enterprise application.


Aspose components provide everything you need to manage Office files, plus much, much more. They are designed with the philosophy of allowing developers to accomplish the greatest results with the least amount of work.

Aspose components provide many powerful time-saving functions. For example, Aspose.Words offers a feature that allows developers to populate a Word mail merge document directly from any .NET data object. It is worth noting that every component in the Aspose family offers its own set of unique and powerful features.

See Also