What is backend development and how do APIs power business websites?

Backend development is the server-side layer of a website or web application: the code, databases, and server logic that process requests, manage data, enforce business rules, and deliver responses to the frontend. It is invisible to the user but determines everything about what a site can do, how reliably it performs, and how securely it handles data.

APIs (Application Programming Interfaces) are the communication layer between the backend and the frontend, and between the website and external business systems. When a user submits a contact form, the frontend sends a request to a backend API endpoint, which validates the input, stores the data in a database, triggers a CRM integration via HubSpot’s API, and returns a confirmation response. This API-driven architecture decouples the presentation layer from business logic, making both independently scalable, testable, and replaceable as requirements evolve.