I'm trying to learn how APIs work at a high level. I want to understand how systems connect, how data is sent and populated, what kinds of information are exchanged, and how authentication works—including API keys, OAuth, and similar approaches. I'm not necessarily planning to build APIs, so I'd like to focus on understanding concepts such as REST and SOAP rather than becoming an expert programmer. The whole topic feels confusing, and I'm not sure where to begin. What learning path or resources would you recommend?
2 Answers
REST is probably the clearest place to start because it’s widely used and relatively straightforward. Find a beginner-friendly REST API walkthrough and pay attention to what the client sends, what the server returns, and how the data is represented. You don’t need to build a production API, but experimenting with a simple example—or using a tool such as Postman—can make the concepts much less abstract. After that, look at SOAP and compare its XML-based messages and stricter conventions with REST’s typical HTTP-and-JSON approach.
APIs vary depending on the service and technology, so it helps to narrow your goal first. Start with one concrete example and learn the general ideas through it: requests and responses, URLs and endpoints, HTTP methods such as GET and POST, headers, status codes, data formats like JSON or XML, and authentication. Once those pieces make sense, it’s easier to compare REST, SOAP, GraphQL, and RPC.
I’m mainly trying to understand REST and SOAP rather than develop APIs, but starting with a simple REST example sounds manageable. I’ll focus on the request, response, and data flow first.