Have you ever come across the term API or application programming interface? An API only states the rules for communication to take place. It is similar to applying for a driver’s license. You can’t sit at home and print a driver’s license for yourself.
You need to go to the local DMV, give them the requisite documents, take the test, and then wait for the result. It is a process that you have to follow. You don’t exactly know what is going on behind the scenes as you wait for the result.
The system took your entries and is working on them. Once the license is ready, it will give you a new one. That is precisely how an API functions. The system lets you use your Facebook account or Apple ID to create new accounts on other services.
It is the system that lets you log in to other websites using your social media profiles. That beloved weather app that you always keep checking? Where does it get all its accurate forecasts? The answer to this question is from an API. A reliable free API gives the front-end app all the required raw weather data.
API Endpoints
In the example above, when you applied for a driver’s license, you didn’t have access to the internal DMV systems or approvers. You did not know who the background checkers were. Similarly, in an API environment, there is the primary system that we want to communicate with.
We, however, do not have any access to the internal functions or code of the system. We can only communicate with the API layer that has been provided. It is similar to the person at the DMV to whom you handed your documents. This point of contact is known as the endpoint.
Protocol
Every endpoint has a few protocols. These protocols determine the type of inputs that you require for the API. They also tell you the results you will get once you put in those inputs. If the wrong inputs are supplied, the request gets rejected. You also have to give the interface an API key. The API key is nothing but an encrypted access code. It is so that they can keep a record of who is accessing the system.
Every system will have its unique API with separate endpoints and protocols. The app you are developing or using can interact with all of the different systems through their APIs. All APIs have a documentation section that tells you how to communicate with the system.
SDK
SDKs are software development kits. These are the sets of code that make it easy for the programmer to use an API. Major systems always give you an SDK bundled with the API. These APIs are downloadable, and you can use them in your software projects. It will make using the system’s API a lot easier.
API Directory
APIs have been around for a while now, and several thousand APIs exist. An API directory houses them, and you should use them to figure out which API will work best in your project. One of the largest API directories out there is Programmable Web.
JSON
It is one of the most important aspects of mobile app development. JSON is a type of data format. The response that you receive from an API is often in this format. If, for instance, you wanted to obtain some information from the Twitter API, you would send a query to Twitter’s endpoint. The reply would be returned to you in JSON format from that endpoint.
Thus, the programmer must understand how the JSON format works and how to parse it. Parsing is a coder’s term for processing. The 3 aspects of JSON formats are:
- Key-Value Pairs: The key describes what the data following it is. The value is the data that is ascribed to that key.
- JSON Objects: When you put a comma between several key-value pairs and then put them inside curly brackets, what you get is a JSON object.
- JSON Arrays: JSON objects are nested inside JSON arrays. JSON arrays are JSON objects separated by commas and inside square brackets.
That’s the basic outline of the data format for all JSON systems.
This article was a brief introduction to the application programming interface systems. And these are some of the fundamental concepts of API development.