Fast & Reliable ZIP Library for C# & VB.NET

Ultimate ZIP is a high-performance and reliable compression component. It lets you easily create and manipulate ZIP, TAR, TGZ, GZ archives on-the-fly as well as browse the contents of a previously created archive right in your .NET cross-platform apps. Written purely in C# with the best design patterns and low-level .NET optimizations applied, it offers performance, reliability, and extensibility to your .NET applications. The package comes with many code snippets and fully documented examples in VB.NET and C# illustrating how to create, zip and unzip archives.

Ultimate ZIP - top compression component for .net

.NET ZIP Component's Key Features

  • Load and create a zip file in memory, stream or file
  • Add, remove, update, move/rename, change attributes, set time of single or multiple files (both recursive and non-recursive modes) within an archive.
  • Password protect files without decompressing the whole ZIP file
  • No temporary files used while zipping and unzipping
  • 1-way and 2-way ZIP synchronization
  • Support real-time ZIP (compress and decompress on-the-fly)
  • Support transactions to improve the compression speed
  • Compatible with WinZip, PKZIP, Info-ZIP, UNIX gZip, and many others
  • ZIP, ZIPX, TAR, TGZ, and GZ archive formats
  • Classic Pkzip encryption or AES encryption
  • 128-bit, 192-bit, and 256-bit AES encryption standard
  • Reads and writes ZIP files on-the-fly. No temporary local or memory files are used
  • Stores archive in memory where intermediate disk storage is not preferred
  • Self-extractor included
  • Support for Zip64 file format. A ZIP archive can be over 4GB and has more than 16384 files
  • Support for BZip2 and BWT compression algorithms
  • Support for the PPMd compression method
  • Support for disk and memory file systems
  • Custom ZLib class is used instead of open-source ZLib compression libraries
  • Support for Deflate and Enhanced Deflate
  • Compatible with Deflate64(tm) by PKWARE
  • 9 compression levels, an individual level can be set for each file
  • Minimized memory footprint
  • Tests files in archives
  • Repairs damaged archives
  • Controls the path information stored in an archive for each file or folder
  • Support for UTF-8 character encoding. Shows correct international characters in filenames and comments
  • Unified File System Across SFTP, FTP and ZIP Libraries
  • Long Path Support on Windows OS
  • Supports ASP.NET application running on the restricted hosting environment (Medium Trust Environment)
  • Application of best coding practices to improve performance for each platform
  • Support for .NET Full Framework, Xamarin iOS, Mac, Android, Mono, .NET CF, .NET Core, and Standard.
  • Full C# source code for the ZIP compression library is available in the Premium licenses
  • Supports .NET 2.0, 3.5, 4.x (VS 2005 to 2017)
  • Also supports WPF, command line (console), ASP.NET, MVC, and service applications.
  • Full C# source code is available in the premium edition
ZIP Code Example

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Supported Platforms

List of the supported platforms

.NET Framework:
2.0, 3.0, 3.5. 4.0, 4.5.x, 4.6.x, 4.7; both 32-bit and 64-bit editions
OS: Windows XP or later
Visual Studio: 2008, 2010, 2012, 2013, 2015, 2017
Xamarin iOS:
Xamarin.iOS 8.6 or later; Xamarin Studio
Xamarin Android:
Xamarin.Android 4 or later; Xamarin Studio
.NET Core 2.0 or above (available soon)
.NET Standard 2.0 or above (available soon)
Universal Windows Platform (UWP)
Version: Windows 10 Mobile, Windows 10 Store Apps and Windows 10 IoT
OS: Windows
Mono and Xamarin Mac:
Version: 3.x, 4.x
OS: Linux, Apple macOS (OS X)
.NET Compact Framework:
2.0, 3.0, 3.5. 3.9
OS: Windows Mobile, Windows CE, Pocket PC, Windows Embedded Compact 2013
Visual Studio: 2008, 2012, 2013

Why Choose Ultimate ZIP

High Performance

Unlike most other competitors' ZIP products, UltimateZip is able to add, delete, and rename files and folders within an archive at once using its own transaction system, making it run faster by reducing the number of repeated I/O operations on disk and memory.

The following features ensure this component runs well:

  • Minimized memory footprint
  • Application of best coding practices to improve performance for each platform, including .NET, Android, iOS and .NET CF

The outcome is that your compression and decompression routines run at maximum possible performance.

the c# zip toolkit is optimized for performance
create, compress, and unzip files easily with intuitive and fully documented API

Intuitive API with many Examples

The zip toolkit is written 100% in C# from the ground up. By applying the best design patterns and using built-in features of .NET and C#, it has clean design and is very easy to maintain and unit test. Unlike some other libraries, the Ultimate ZIP does not use any third-parties libraries and unsafe blocks. As a benefit, it is stable and permission requirements are minimized. The component can be used in any .NET languages like C#, VB.NET, J#, C++, and F#.

We know that having intuitive API isn't enough. So we back it with the fully documented XML files and online manual. You will find that we have example code snippets for many classes and class members


The component offers a comprehensive set of classes for compressing and decompressing archive files, providing the developer with needed to incorporate compression and decompression functionality in an application as listed below:

TAR, TGZ, and GZ

The ArchiverBase class helps you handle items within TAR, TGZ, and GZ archives as easily as if they were local disk files or folders. The Ultimate ZIP is compatible with USTAR format TAR archives and GNU TAR archives.

zip component with self-extracting feature

Self-extracting ZIP

With our .NET ZIP library, you can create new self-extracting ZIP files or convert existing ZIP files into self-extracting archives. The component includes the following self-extracting ZIP file features:

  • Self-extracting archives that are highly customizable.
  • Self-extracting archives can span multiple disks
  • Self-extracting archives can perform all the ZIP operations supported by the component

Real-time ZIP

The RealTimeZip class lets you read/write ZIP archives on-the-fly without using any intermediate disk or memory storage. As a benefit, the archive size or number of files does not impact to the memory usage and the entire compression/decompression is secured so that the unauthorized access or modification of files during the archive creation process is limited. RealTimeZip supports BZip2, BWT, Deflate, and PPMd compression methods and the AES encryption algorithm.

Real-time ZIP feature is included in our .net zip library
One code can be used for ZIP, FTP and SFTP

Unified API across SFTP, FTP and ZIP products

To save your effort writing a number of classes for different systems such as FTP, SFTP, ZIP, Local Disk, and Memory, we have introduced the Unified File System, making the file and directory management on these systems seamless. That unified API allows you to use the same code to transfer files and directories directly between two different systems. As a benefit, you may need to write only one class that works with all systems. The complicated work is done by the File System library and there is no need to learn more about other File Transfer Protocols. For example code, please visit this topic.

Advanced File Management

The .net zip component provides synchronous or asynchronous file compression/decompression as well as the ability to deep search, delete, move, set properties, check existence, synchronize, and compare files and directories to your applications, offering an easy way to manage files.

C# ZIP with advanced file management feature

Long Path Support on Windows OS

Our FTP, SFTP and ZIP components fully support long path on Windows OS. All the file and directory management API permit an extended-length path for a maximum total path length of 32,767 characters. You will never get "Path too long" exception from .NET Framework when using our components.

Manipulate File List On-the-fly

Want to add and update the transfer list while files and folders are still being compressed/decompressed? The File System library included in Ultimate ZIP lets you have full control of the progress file list. In addition, you will have detailed compression/decompression statistics when the process completes.

ultimate zip can be used in powershell & sql-ssis

Compress Files in PowerShell and SQL-SSIS

Our components are also helpful in PowerShell and SQL-SSIS environments. You can compress file in PowerShell and integrate it to SQL-SSIS package easily.

ASP.NET Medium Trust Environment

We simply support ASP.NET Medium Trust Environment. The only configuration needed for that environment is turning on the MediumTrust security setting.

Task-based Asynchronous Patterns with async and await

The Ultimate ZIP now fully supports asynchronous methods. You can initiate an asynchronous operation in two ways:

  • Task-based approach: Use async and await (C#) or Async and Await (VB.NET) keywords introduced in Visual Studio 2012
  • Event-based approach: Handle an asynchronous event and then calling the corresponding asynchronous method.
zip async await

Other Features

  • Support UNC format
  • Built-in Zlib stream class


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