What is an API? A Beginner’s Guide to APIs

The client sends a request to the server and the server responds to the client regarding that request. A protocol is nothing but a set of rules that computers follow to communicate. Any computer that doesn’t follow the protocol breaks the communication thread. A client asks for some resource, say for example a photo, and the server sends that photo to the client. API (Application Programming Interface) testing is a kind of software testing that analyzes an API in terms of its functionality, security, performance, and reliability.

  • Microservices architecture has become more prevalent with the rise of cloud computing and, together with containers and Kubernetes, is foundational to cloud-native application development.
  • Because a web service exposes an application’s data and functionality to other applications, in effect, every web service is an API.
  • This same principle is used on modern mobile operating systems like iOS and Android, where mobile apps have permissions that can be enforced by controlling access to APIs.
  • APIs are classified both according to their architecture and scope of use.
  • After understanding these concepts, you can try working on them by implementing some of the concepts in projects.
  • The main use of Library-based API is that the market quotes can be pulled, orders can be sent or modified, historical data can be extracted, etc. with help of the libraries.

A Web API or Web Service API is an application processing interface between a web server and web browser. REST API is a special type of Web API that uses the standard architectural style explained above. The API client is responsible for starting the conversation by sending the request to the API server. For instance, a user might initiate an API request by entering a search term or clicking a button. API requests may also be triggered by external events, such as a notification from another application.

Brokers’ API to automate trading

Suppose one of the company’s partners develops an app that helps people find books on bookstore shelves. This improved experience brings more shoppers to the bookstore—the distributor’s customer—and extends an existing revenue channel. As you browse redhat.com, we’ll recommend resources you may like.

api meaning

The term API may refer either to the specification or to the implementation. Whereas a system’s user interface dictates how its end-users interact with the system in question, its API dictates how to write code that takes advantage of that system’s capabilities. A developer extensively uses APIs in his software to implement various features by using an API call without writing complex codes for the same. We can create an API for an operating system, database system, hardware system, JavaScript file, or similar object-oriented files. Also, an API is similar to a GUI(Graphical User Interface) with one major difference.

Phase 2: Social media APIs

The latest version, OAS3, includes with hands-on tools, such as the OpenAPI Generator, for generating API clients and server stubs in different programming languages. APIs function by passing information from a service provider to an application via an API endpoint. They are often a key component to interoperability in software development, often facilitating the transfer of data via request and response. In short, APIs let you open up access to your resources while maintaining security and control. API security is all about good API management, which includes the use of an API gateway.

api meaning

They’ve also included a helpful introduction to help you get started. The term “API” has been generically used to describe connectivity interfaces to an application. However, over the years, the modern API has taken on some unique characteristics that have truly transformed the technology space.


The extra effort of producing an API can be justified, as they often help a program’s relevance and longevity by allowing it to be accessed by other programs. Too much access, however, can result in an application’s being copied; in order to avoid copying, some organizations try to keep their APIs secret or constantly change them. Many computer programmers consider APIs a good compromise between the flexibility of open-source programs and the rigidity of closed applications. In REST APIs, the calls and responses go through different layers. As a rule of thumb, don’t assume that the client, and server applications connect directly to each other. There may be a number of different intermediaries in the communication loop.

Despite their nicknames, webhooks are not APIs; they work together. Making technology public can lead to novel and unexpected outcomes. For our book distributing company, new firms―a book borrowing service, for example―could fundamentally change the way they do business.

Creating more scalable systems

They are typically a URL exposed by the server that enables other systems to connect to the endpoints. Endpoints are where a developer’s code interacts with an organization’s code and data. For mobile and web applications, AppSync also provides local data access when devices go offline. Once deployed, AWS AppSync automatically scales GraphQL API execution engine up and down to meet API request volumes. To use API trading, traders need to have a trading account with a forex broker that supports API trading.

api meaning

In recent years, the OpenAPI specification has emerged as a common standard for defining REST APIs. OpenAPI establishes a language-agnostic way for developers to build REST API interfaces so that users can understand them with minimal guesswork. Remote APIs are designed to interact through a communications network. By remote, we mean that the resources being manipulated by the API are somewhere outside the computer making the request.

However, the ability to support multiple formats for storing and exchanging data is one of the reasons REST is a prevailing choice for building public APIs. APIs can be categorized by use case, including data APIs, operating system APIs, remote APIs and web APIs. A single API can have multiple implementations (or International Commerce Erp none, being abstract) in the form of different libraries that share the same programming interface. One purpose of APIs is to hide the internal details of how a system works, exposing only those parts that a programmer will find useful, and keeping them consistent even if the internal details change later.

api meaning

Users communicate with an API when plotting travel routes or tracking items on the move, such as a delivery vehicle. A popular API example is the function that enables people to log in to websites by using their Facebook, X, or Google profile login details. This convenient feature allows any website to use an API from one of the more popular services for quick authentication. This capability helps save users the time and hassle of setting up a new profile for every web application or new membership. API documentation is like a technical instruction manual that provides details about an API and information for developers on how to work with an API and its services. Well-designed documentation promotes a better API experience for users and generally makes for more successful APIs.

API publishing and management

An interface is a means of interacting with a system’s internals. Generally, the interface’s job is to simplify and concentrate internal capabilities into a form that is useful for the client. What is different about APIs and UIs is that they interface with different types of clients. All but the most trivial software uses capabilities provided by other components. A software program calls a component’s API to access its capabilities. In addition to using other components, most software is used as a component by other programs, as shown in Figure 2.

Websocket APIs

With an autonomous exchange of data and requests, APIs dramatically reduce the time and effort involved in checking for available flights or accommodation. Popular forex trading platforms MetaTrader and cTrader are well-known examples of third-party software that connects to your forex broker via API. Read our MetaTrader guide to learn more about the platform, and check out our MetaTrader 5 guide to get an in-depth look at the newest version of the MetaTrader software. My MT4 vs MT5 guide details the differences between the two versions of MetaTrader to help you make an informed choice. You can read the full list of supported functions and features on OANDA’s developer page.


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