TECH BASICS
API
How different pieces of software talk to each other.
The simple version
An API (Application Programming Interface) is a set of rules that lets one piece of software ask another piece of software for something — data, an action, a result — without needing to know how it works inside.
For example
When a weather app shows today's forecast, it's not measuring the weather itself — it's calling a weather API that returns the data, and the app just displays it.
Go deeper
APIs are usually described with documentation — a kind of menu of everything you're allowed to ask for. Companies often sell access to their API directly (this is how a lot of B2B software makes money), and 'API-first' has become a common way to build products so other tools can plug into them easily.
Why it matters
APIs are everywhere in modern tech careers — you'll see the word in engineering job descriptions, but also in sales, partnerships, and product roles, since so many companies' products and revenue depend on how well their APIs work.