Stateless architecture is a design principle in which each request from a client to a server is treated as an independent transaction. This means that the server does not store any information about the client's previous requests. Each request must contain all the necessary information for the server to understand and process it, which simplifies server design and improves scalability. In a stateless system, if a server fails, any client can connect to another server without losing context. This approach is commonly used in web services and APIs, such as those following the REST architectural style, where each interaction is self-contained and does not rely on stored data.