Open source software is developed with source code freely available for anyone to view, modify, and distribute. This collaborative approach allows developers worldwide to improve software, fix bugs, and add features. Municipal governments increasingly consider open source options for everything from website content management to geographic information systems. Benefits include lower licensing costs, ability to customize software, avoiding vendor lock-in, and benefiting from global developer communities. Challenges include potentially higher implementation complexity and need for technical expertise. Major open source projects include Linux operating system, WordPress, and numerous specialized applications used by governments.