Lecture 6

APIs

How software talks to software — and why every product you design is really a bundle of APIs.

Hour 1 — The contract

  • What an API is: a menu of things you can ask another program to do
  • REST in plain language: URLs as nouns, methods as verbs (GET, POST)
  • GraphQL in one idea: ask for exactly what you need
  • API keys, rate limits, and why "free" APIs aren't
  • Reading API documentation as a designer — enough to know what's possible
  • The weather API walkthrough: request in, JSON out, pixels rendered

Hour 2 — Studio

  • Exercise: Exercise - API MashupExercise - API Mashup
    Build a page powered by someone else's data

    Use a public API to make a small, well-designed page that displays live data — and understand the request/response loop underneath it.

    Ideas


    Weathe...
    — use AI to build a small page powered by a public API (weather, movies, maps, transit)
  • JSON literacy: reading the response with your own eyes

Homework

  • Write a one-paragraph explanation of how an API works, as if to a client. (This is the official "API Concept Explanation" assignment.)