Software platform in the context of Widget engine

Systems programming, or system programming, is the activity of programming computer system software. The primary distinguishing characteristic of systems programming when compared to application programming is that application programming aims to produce software which provides services to the user directly (e.g. word processor), whereas systems programming aims to produce software and software platforms which provide services to other software, are performance constrained, or both (e.g. operating systems, computational science applications, game engines, industrial automation, and software as a service applications).

Systems programming requires a great degree of hardware awareness. Its goal is to achieve efficient use of available resources, either because the software itself is performance-critical or because even small efficiency improvements directly transform into significant savings of time or money.

A killer application (often shortened to killer app) is any software that is so necessary or desirable that it provides the core value of some larger technology, such as its host computer hardware, software platform, or operating system. Consumers would buy the host platform just to access that application, possibly substantially increasing sales of its host platform.

A software framework is software that provides reusable, generic functionality which developers can extend or customize to create complete solutions. It offers an abstraction layer over lower-level code and infrastructure, allowing developers to focus on implementing business logic rather than building common functionality from scratch. Generally, a framework is intended to enhance productivity by allowing developers to focus on satisfying business requirements rather than reimplementing generic functionality. Frameworks often include support programs, compilers, software development kits, code libraries, toolsets, and APIs that integrate various components within a larger software platform or environment.

Unlike a library, where user code controls the program's control flow, a framework implements inversion of control by dictating the overall structure and calling user code at predefined extension points (e.g., through template methods or hooks). Frameworks also provide default behaviours that work out-of-the-box, structured mechanisms for extensibility, and a fixed core that accepts extensions (e.g., plugins or subclasses) without direct modification.