Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized software development model that encourages open collaboration.

Open source software makes its code available for review, which increases the likelihood that security vulnerabilities are found and corrected quickly. Closed source software may be secure as well, but you have to trust the developers and company who made it.

Doesn't "open source" just mean something is free of charge? No. This is a common misconception about what "open source" implies, and the concept's implications are not only economic. Open source software programmers can charge money for the open source software they create or to which they contribute.