DoorDash didn't build its own maps. It didn't build its own payment processor. It didn't build its own text messaging system. So how does one app do all of that? The answer is APIs, the quiet connective tissue that lets different systems talk to each other, and this guide explains exactly how.
You'll learn how a request actually gets built and sent, how one application proves its identity to another before anything happens, why APIs are organized around things called endpoints, and what happens in the moments between an application sending a request and getting a response back. The guide also compares REST and SOAP, two different approaches to building APIs, and explains why REST became the standard almost everywhere.
APIs power everything from online payments to weather apps to single sign-on, which also makes them a frequent target for attackers. This guide closes with two real, common ways APIs get abused, so you come away understanding not just how APIs work, but why getting them right matters.
What you'll learn
- Why applications rely on other applications instead of building every feature themselves
- How to actually read a basic API request and response
- What terms like endpoint, JSON, and status code mean in practice
- How an application proves who it is before an API will respond to it
- The difference between REST and SOAP, and why REST became the dominant approach
- Two real ways APIs get abused, and why understanding them matters
Who this is for
Developers, product managers, or anyone who's heard "we'll just use their API" in a meeting and wants to actually understand what that means. No coding experience required.
Frequently asked questions
Do I need programming experience to understand this guide?
No. It's written for people who've never written code, though developers new to APIs will get value from it too.
Does this teach me how to build an API?
Not directly. It's focused on understanding how APIs work and communicate, which is the foundation you'd need before building one.
What's the difference between REST and SOAP?
That's one of the core comparisons in the guide, including why REST won out as the dominant approach for most modern APIs.