The role of a tech stack in web development projects is to provide a structured combination of technologies that support the development, deployment, and operation of web applications. A tech stack typically consists of programming languages, frameworks, libraries, and tools chosen based on project requirements and team expertise. By selecting an appropriate tech stack, developers can ensure that components integrate seamlessly, optimize performance, and enhance scalability. The right combination of technologies greatly influences the speed and efficiency of the development process, thereby impacting the overall success of web projects.