It refers to something that can be modified because its design is publicly accessible. Open source software is software whose source code is available for modification or enhancement by anyone. Most open source licenses require software developers to release their source code when they sell software to others, many open source software programmers find it more lucrative to charge users for software services and support rather than for the software itself. This way, their software remains free of charge and they make money helping others install, use, and troubleshoot it.
Implementation of E-Government projects need investments in IT thus, assessment made with respect with these investments for information technology increases interest in the opportunities by open-source software, and increases their potential for their usage in E-Government economically advantageous and relevant.
Few open source providing functions similar to commercial software are
| Software Type | Open source Software | Commercial Software |
| Project Management | Project.net | Microsoft Project |
| Office Applications | Libre Office / OpenOffice | Microsoft Office |
| PDF Creation | PDFCreator | Adobe Acrobat |
| Vector Drawing | Inkscape | Adobe Illustrator |
| Image & Photo Manipulation | GIMP | Adobe Photoshop |
| Statistical and Graphical Analysis | GNU R | SAS, SPSS |
| Programming & IDE | Eclipse | Microsoft Visual Studio |
| Data Mining | RapidMiner | SPSS, Excel |
| Backup | Amanda, Bacula | NetVault Backup |
| Server | RedHat Enterprise Linux, CentOs Linux | Microsoft Windows Server |
| Desktop Operating System | RedHat Linux, CentOs Linux | Windows XP, Vista, 7 |
| Business Intelligence (BI) | Pentaho BI Suite | Oracle, IBM, Informatica |
| E-mail Server | Zimbra | Microsoft Exchange Server |
| Enterprise Resource Planning (ERP) | OpenERP, Openbravo | SAP, Oracle, Microsoft Dynamics, SAP |
| Web Application Development | PHP | Microsoft ASP.Net |
| Relational Databases | MySQL | Microsoft SQL Server |
| Web Server | Apache web server | Microsoft IIS |