I want to understand APIs at a high level rather than necessarily build them from scratch. I'm trying to learn how different systems connect, how data is requested and returned, what kinds of information are sent in API requests and responses, and how authentication works—including API keys, OAuth, and similar approaches. The topic feels overwhelming, especially since there are different API styles such as REST and SOAP. I don't need to become an expert developer, but I'd like a clear starting point and some practical learning advice.
2 Answers
REST is probably the best place to begin because it’s widely used and relatively approachable. Learn the basics of HTTP first: URLs, methods like GET and POST, headers, request bodies, status codes, and JSON responses. Then look at a simple REST API example and see how a client sends a request and processes the returned data. Once that makes sense, add authentication and compare API keys, bearer tokens, and OAuth. SOAP is worth learning separately afterward since it commonly uses XML and has a more formal structure.
APIs share some general ideas, but the details depend heavily on the service and API style. REST, SOAP, GraphQL, and RPC all work differently, so it helps to choose one narrow example instead of trying to learn every kind at once. Start with a specific service or use case, then expand your understanding from there.
I’m mainly trying to understand REST and SOAP conceptually rather than build APIs myself, but I’ll use a simple REST example to make the ideas less abstract.