An API (application programming interface) is a set of protocols through which two systems communicate with one another. These systems can be computers, platforms, programs, or apps.
An API contains information about parameters, return values, and more that provide developers with code libraries and standards, so they don’t have to come up with their own when extending the functionality of two or more systems.
An API makes it much easier to transfer, change, and sift through large amounts of data, making it essential for streamlining the management and exchange of information in today’s enterprises.
How to Use an API: Best Practices
Below are some ways you can experiment with asking for and posting information with APIs.
Get an API key
In order to use an API, you need an API key. Most APIs prompt you to log in to verify your identity — for example, signing in with your Google account. After verifying your identity, the API gives you a string of unique letters and numbers, which is your API key.
Find an HTTP client online
Find an HTTP client online, like Apigee or Postman. These are ready-made, often free tools that help you structure your requests to APIs. They contain dozens of APIs whose endpoints are there to play with, such as Instagram and its media search endpoint.
Build a URL
You can explore data from an API by building a URL from existing API documentation. This will require some familiarity with the syntax of the API’s documentation in order to structure your request to it.
Read more on TechnologyAdvice.com: 5 Capabilities an API Management Tool Should Have
How Does an API Work?
To understand how APIs work, there are three main players:
- User: Person who initiates a request for information
- Client: Computer that sends the request to the server
- Server: Computers that house data and respond to the client request
The client routes the request to the server and, if the user is authorized for access, the client returns the desired information to the user.
Programmers publish documentation about the data stored within a server, such as which endpoints hold which pieces of information.
An outside user who wants to access a piece of information on that server sends a call through a client using a coding language like XML or JSON. This language contains actions like the following:
- GET to receive information from the server
- PUT to add or change existing information in the server
- POST to enter new information into the server
- DELETE to remove information from the server
Not all APIs use all of these verbs. SOAP APIs, for instance, are POST only. Fortunately, for those with limited coding knowledge, programs can run these searches.
Read more: How Do APIs Work?
Types of APIs
There are several types of APIs, REST being the most common. They each have their own architecture and use cases, and don’t necessarily share the same language.
Representational State Transfer APIs are the most commonly used today because they focus on end-user readability and ease of consumption.
A user looking for specific information makes a call or request through a hypertext transfer protocol (HTTP) client, such as https://www.google.com/maps, to search for information. The client then sends the call or request to the Google Maps server.
If the end user is authorized to receive the information, the client receives the information through HTTP, usually in XML or JSON. However, the information usually gets to the end user in a readable format (not XML or JSON) because a developer makes it more readable to the end user.
REST APIs simplify and standardize communication between computers. Developers can change up the display on the client-facing side, while working on data storage and manipulation on the server-side of an app. REST APIs are also scalable, so they can accommodate growing data sets and their complexity.
Common examples of REST APIs include Google Maps, Facebook’s Graph API, and Twitter.
A GraphQL API has a descriptor for any type of data and can be used in a variety of database schemas. Unlike REST APIs, GraphQL APIs are organized according to types and fields instead of endpoints. This allows users to only ask for what’s possible and quickly access full data capabilities through a singular endpoint — even if mobile network connection is slow.
GraphQL API is flexible and can evolve by allowing new fields and types to be added without affecting existing searches, providing aps with continuous access to new features.
gRPC stands for Google Remote Procedure Call and is an open-source data exchange technology. It allows client applications to communicate with service endpoints over Google Cloud Platform products.
Simple Object Access Protocol (SOAP) is a standard communication protocol system that allows processes using different operating systems, such as Linux and Windows, to communicate via HTTP and XML. SOAP-based APIs are designed to create, recover, update, and delete data, so they only work with POST HTTP request methods. A legacy protocol, SOAP is used in enterprise applications today where security is prioritized over performance.
A webhook API, also referred to as a web callback or HTTP push API, is a type of API that remotely and automatically delivers real-time data to users who subscribe to receive real-time updates. Apps that typically use a webhook API include instant messaging apps or web forms, such as Google Forms.
A WebSocket API establishes a continuous bi-directional flow of communication between the client and the server without needing to set up a new connection each time a message is sent. A user can send messages to a server through a WebSocket API and get event-driven responses. Apps that contain social feeds or financial tickers would typically use a WebSocket API.
Read more on TechnologyAdvice.com about managing APIs: The Best API Management Software and Tools
Now That You Know How to Use an API
APIs open up and streamline gateways between new and existing platforms. They provide standardized protocols that make it easier for companies to integrate their applications and services across various platforms. So, for instance, when you want to get notified about changes to a Google Doc in Slack, an API sets up a connection between Slack and your Google suite to allow Slack to receive and answer requests from Google.
You don’t have to be a developer to make use of APIs in your business, but establishing more complicated connections between enterprise systems will likely require specific development expertise.