Glossary / API
What is an API?
An API (application programming interface) is a defined way for one piece of software to ask another for data or to do something, such as "get this customer's orders" or "charge this card".
A restaurant menu is a good picture of an API. It lists what you can order and how to ask for it; you do not need to know how the kitchen works.
Apps use APIs all the time. Your frontend calls your own backend's API to load and save data. Your backend calls other companies' APIs to send email, take payments, show maps or use an AI model.
Most APIs need a key to prove who is calling. Those keys are secrets and belong on the server, never in the browser.
Examples
- A payment API to charge a card
- A maps API to show a location
- An AI API to summarise text
Questions
What is a REST API?
REST is a common style of API that uses web addresses and standard actions: get to read, post to create, put or patch to change, delete to remove.
Are APIs free?
Some are, many have a free tier, and others charge by usage. Check limits and pricing before building something that depends on one.