What Is an API? A Plain-English Guide With a Real Example

⏱ 2 min readUpdated 28 September 2026

An API (Application Programming Interface) is a menu a program offers to other programs: “ask me for these things, in this format, and I’ll answer”.

In this article
  1. The restaurant analogy
  2. A real request
  3. Parts you will meet
  4. Into Excel (no code)
  5. Into Python

The restaurant analogy

You (your program) don’t walk into the kitchen (the other company’s database). You give the waiter (the API) an order from the menu (the documentation), and get your dish (the data, usually JSON).

A real request

Many APIs work with a simple web address. For example a currency API might accept:

GET https://api.example.com/latest?base=USD&symbols=INR,EUR

and reply with JSON such as {"base":"USD","rates":{"INR":74.9,"EUR":0.88}}.

Parts you will meet

Term Meaning
Endpoint The URL for one kind of request
GET / POST Read data / send data
Parameters Options after ? in the URL
API key Your password for the API — keep it secret
Rate limit How many requests you may make per minute/day
Status code 200 OK, 401 bad key, 404 not found, 429 too many requests

Into Excel (no code)

Data → From Web, paste the URL, then expand the JSON in Power Query. Refresh gives new data.

Into Python

import requests
r = requests.get("https://api.example.com/latest", params={"base": "USD", "symbols": "INR"}, timeout=30)
r.raise_for_status()
print(r.json()["rates"]["INR"])
⚠️ Never put an API key in a shared workbook or a public GitHub repository. Store it in an environment variable or a separate config file.
✨ Ask AI about this article

Stuck on a step? Ask a question and the AI answers using this article.

Free · AI can be wrong