Anyone who wants to use the internet, PC, and/or mobile phone for communication needs simple and fast client-server programs. With the help of this book, you will be able to easily program them yourself, benefiting from the fact that it is often possible to do so for free using open-source software. The book provides a quick and easy introduction to programming web browsers and web servers using sockets. With the "dream team" of C and Linux, you have full access to the source code and thus unlimited configuration options. The applications presented here are lightweight, meaning they are extremely resource-efficient and therefore particularly suitable for embedded systems. Through practical exercises, web browsers and web servers will be built step by step, which the reader can expand and develop for their own specific problems.