The article discusses the challenges faced by developers while building applications based on large language models (LLMs) such as high costs of API calls and poor performance due to response latency. It introduces GPTCache, an open-source semantic cache designed to improve efficiency and speed of GPT-based applications. GPTCache stores LLM responses in the cache, allowing users to retrieve previously requested answers without calling the LLM again. The article explains how GPTCache works, its benefits including drastic cost reduction, faster response times, improved scalability, and better availability. It also provides an example of OSS Chat, an AI chatbot that utilizes GPTCache and the CVP stack for more accurate results.