API Gateway
advancedDefinition
A single front door that receives every request to a system's APIs and passes each one to the right service behind it, often checking sign-in and limits on the way.
In the wild
A travel app's phone screens send every request to one API gateway, which sends flight searches to one service and hotel bookings to another.
More from Architecture
Caching
Keeping a ready copy of something slow to fetch or work out, so the next time it's needed it can be handed back right away.
CAP Theorem
A rule for systems that keep copies of data on several computers: if the computers lose touch, the system must choose between refusing some requests to keep every copy in agreement, or answering anyway and letting copies briefly disagree.
CDN (Content Delivery Network)
A network of computers around the world that keep copies of a website's images and files, so each visitor gets them from somewhere nearby and pages load faster.
Client-Server Architecture
The basic shape of most apps: the client (the browser or phone app in front of you) asks for things, and the server (a computer somewhere else that holds the data) answers.
Event-Driven Architecture
A way of building software where one part announces that something happened and any other part that cares reacts to it, instead of each part calling the others directly.
Eventual Consistency
When data is stored in several places, an update may reach some copies before others, so they can briefly disagree before they all catch up.