High Quality Content by WIKIPEDIA articles! An open-source license is a copyright license for computer software that makes the source code available for everyone to use. This allows end users to review and modify the source code for their own customization and/or troubleshooting needs. Open-source licenses are also commonly free, allowing for modification, redistribution, and commercial use without having to pay the original author. Some open-source licenses only permit modification of the source code for personal use or only permit non-commercial redistribution. All such licenses usually have additional restrictions such as a requirement to preserve the name of the authors and a copyright statement within the code. One popular set of free open-source software licenses are those approved by the Open Source Initiative (OSI) based on their Open Source Definition (OSD).