API (Application Programming Interface)

Detailed definition

An API (Application Programming Interface) is an interface layer that lets two pieces of software talk to each other through a predefined contract. It is like a controlled door a system opens so others can use specific data or functions in a secure, consistent way. In the enterprise, APIs are used mostly for integration: they are how an ERP shares stock, order and invoice data in real time with an e-commerce site, marketplace, accounting or CRM system. Common protocols are REST and OData; webhooks handle event-based notifications. Well-designed APIs are versioned, protected with authentication and authorization, and include rate limiting and error handling. Platforms such as SAP BTP Integration Suite are used to manage, monitor and secure APIs centrally. An API-based architecture reduces manual data entry, keeps a single source of truth across systems and forms the backbone of automation; it also frequently feeds ETL/ELT data pipelines.