PyPi (Python Package Index) and npm (Node Package Manager) are popular online repositories used for sharing, discovering, and installing packages for Python and JavaScript, respectively. Developers use these repositories to access a wide range of pre-built libraries and tools, accelerating software development and ensuring code reusability. However, because they are open to public submissions, attackers sometimes upload malicious packages, making it essential for users to verify sources and maintain good cybersecurity practices. Monitoring dependencies and using trusted packages can help mitigate risks associated with supply chain attacks.