Breakneck is a .NET SaaS boilerplate that aims to simplify the backend API development process by offering crucial features like user authentication, billing solutions, and email services. By utilizing a vertical slice architecture, it minimizes boilerplate code and allows developers to concentrate on feature implementation. The platform facilitates metered endpoints for effective usage tracking and offers customizable authentication options, including JWT and API keys, while seamlessly integrating with Stripe for managing subscription billing. Automated testing capabilities are enhanced through TestContainers, which support both unit and integration testing against actual database instances. Additionally, background tasks are efficiently handled using Hangfire, and users can create templated emails with ease. Breakneck prioritizes a clean, maintainable code structure with minimal abstractions, ultimately easing the cognitive burden on developers. This framework is well-suited for constructing a variety of client applications, such as web, mobile, and desktop solutions, establishing itself as a solid backend foundation that developers can rely on. In essence, it serves as a comprehensive toolset for rapid and efficient API development, catering to the diverse needs of modern application development.