MicroSIP is a lightweight, open-source software application that enables users to make Voice over IP (VoIP) calls using the SIP (Session Initiation Protocol) standard. It is designed to be simple, easy to use, and resource-efficient, making it an ideal choice for low-resource devices, such as older computers, and for users who need a minimalistic VoIP client. MicroSIP allows users to initiate audio and video calls, as well as exchange messages, via SIP-based VoIP networks.