An
open-source license is a type of
license for
computer software and other products that allows the
source code,
blueprint or design to be used, modified and/or shared under defined terms and conditions. This allows end users to review and modify the source code, blueprint or design for their own customization, curiosity or troubleshooting needs. Open-source licensed software is mostly available
free of charge, though this does not necessarily have to be the case. Licenses which only permit
non-commercial redistribution or modification of the source code for personal use only are generally not considered as open-source licenses. However, open-source licenses may have some restrictions, particularly regarding the expression of respect to the origin of software, such as a requirement to preserve the name of the authors and a copyright statement within the code, or a requirement to redistribute the licensed software only under the same license (as in a
copyleft license). One popular set of
open-source software licenses are those approved by the
Open Source Initiative (OSI) based on their
Open Source Definition (OSD).