Everything you need to know about an API

What is an api? and why should you care? Read and know everything there is about API and use it in your next project.


Abhiraj Bhowmick

3 years ago | 8 min read

You’ve probably heard the terms API, Public API, or Web API before. These are often used by software companies when speaking about an application, operating system, or website. They are used everywhere in today’s world and offer a tremendous benefit. But have you ever wondered what an API actually is, or how to use it? 

What is an API?

An API (Application Programming Interface) is a set of functions that allows applications to access data and interact with external software components, operating systems, or microservices.  To simplify, an API delivers a user response to a system and sends the system’s response back to a user. You click “add to cart;” an API tells the site you added a product to your cart; the website puts the product in your cart, and your cart is updated.

You may hear the term “microservices” come up in relation to API. These, however, are not the same. Microservices are a style of architecture that divides functionality within a web application. While API is the framework in which developers interact with a web application. Microservices can actually use API to communicate with each other.  

API lets a developer make a specific “call” or “request” in order to send or receive information. This communication is done using a programming language called “JSON.”  It can also be used to make a defined action such as updating or deleting data. There are four basic request methods that can be made with API:

  1. GET – Gathers information (Pulling all Coupon Codes)
  2. PUT –  Updates pieces of data (Updating Product pricing)
  3. POST – Creates (Creating a new Product Category)
  4. DELETE – (Deleting a blog post)

So What is JSON and why is it used?

JSON (JavaScript Object Notation) is used to represent data on a server. It’s fairly easy to read by humans, and easy for machines/applications to understand. This is easy to understand as it’s outputted in key/value pairs, with the key on the left, and a value on the right. Keys are a fixed object defined by the application and will remain the same as with “category.” Whereas the values will be unique, such as “Shirts.”

What is an API Request?

There are several components of an API Request in order for it to function. Let’s go over these individuals and how they can be used to build a request.


There are two key parts to an endpoint that are used when making an API request. One of which is the URL. It may look like a regular URL but if you plug it into a web browser, you will receive a 404 error message. The second part is the path. The path will vary depending on what you are trying to accomplish. When we put these two parts together, we get a complete endpoint


Headers provide information to the client and server. Common examples of a header would be authentication credentials such as an “Auth Token” or “Client ID”. These credentials are provided to you automatically when you create an API Account. Another common header is referred to as the “Content-Type,” which informs the server about what type of content will be sent. For example, a commonly used content type is  “application/JSON” which lets the server know, we are sending JSON data across. 


Methods are the actions taken when sending a request. Think back to the beginning when we discussed GET, PUT, POST, and DELETE. These are all API Methods.  


The request data, also commonly referred to as the “body,” is information that will be either sent to or returned by a server. In the previous discussion of JSON, you can see an example of API data. The body of a request will sometimes require specific information before it can be delivered. An example of this is if you are editing a single product, the Product ID will be required before any change can be made.

What about REST & SOAP APIs?

While API follows a specific set of rules that determine how programs communicate with one another. REST & SOAP define how the API is presented. Each is similar in functionality but has several key differences and uses cases. 

REST stands for “Representational State Transfer” and is the set of rules that developers follow when creating an API. REST is read using JSON as we covered previously. One of these rules is that the API should be designed in a way that is easy to use and will make sense for developers. An example of not following this rule would be to have the product endpoint “prod_839” instead of just “products.” This could cause the API to be fairly unpleasant to work with. 

SOAP or Simple Object Access Protocol is another design modal for web services. Instead of the typical JSON that REST API uses. SOAP uses a language known as Extensible Markup Language (XML). XML is designed to be machine- and human-readable. SOAP follows a strong standard of rules, such as messaging structure and convention for providing requests or responses. 

This article in general refers to REST API standards as it’s mostly used in today’s world. Major companies such as Google, Amazon, eBay, and even BigCommerce use REST APIs. REST is generally the preferred choice amongst software developers.

Everyday Examples of APIs

API helps developers quickly deliver information to consumers and is used every day in today’s world. From shopping online, browsing a social media app, or playing a game on your smartphone. Every time you visit a page online, you’re interacting with API. Here are some real-world examples of how you interact with API and may not even realize it.

Going to a bank.

Think of yourself as a user and a bank teller as an API, while the bank is the system you interact with. When you want to take some money out of your account, you walk up to the teller(API) and say “I’d like $1,000 from this account”. The teller (API) then goes to the back, tells the bank manager (the system) “Mr/Ms.X would like $1,000”, the bank manager (the system) gives the teller (API) $1,000 who eventually gives it to you. As you can see the API, is a messenger between your needs and the system. 

Searching for hotels.

When you go onto a travel site, it may be linked to 10 other travel sites to find the best deal for you. When you input details like Atlanta, 2 nights, 1 Room, you send this request to those 10 different travel sites. The API takes your request for that specific location, date range, and room and pings the 10 sites, who send back the deals they have found. You look through the 10 deals and pick the best one. Again, the API is a messenger for your requests.

Finding a Facebook profile.

Stalking your ex? Hopefully not, but thanks to APIs, you can do it easily! If you type in “John Smith” on Facebook, the API informs Facebook’s servers that you’re looking for John Smith. Facebook then sends you a list of all the profiles that match that name (with factors like vicinity to you, or mutual friends). Now you can find John Smith! 

Finding a new restaurant.

Let’s say you are traveling to a new city or state. You’ve just dropped everything off at the hotel and decide to grab some lunch. You grab your smartphone and look up restaurants nearby. Quickly you are shown dozens of local restaurants right outside your hotel. Thanks to Google Maps API; they are able to easily display business hours, reviews, phone numbers, and even times they are likely to be busy. 

Staying up to date on social media. 

You’re stuck in a cab while in rush hour traffic. The worst, I know! You decide to kill some time and decide to catch up on what’s happening in the world of sports. You open Twitter and navigate to the ‘Sports’ section. Twitter’s API allows you to easily see various tweets relating to your favorite team winning the play-offs. You were even able to rub it in your friend's face that his team lost by retweeting the final score. From here Twitter knows to take this tweet, and display it to everyone who follows you.

Why Modern Ecommerce Sites Use APIs

API’s offer a wide range of benefits for Ecommerce Sites. They can help consumers easily find products, grow a company’s brand, or even expand their earning potential by selling products on various marketplaces such as eBay, Amazon, and Facebook. Listed below are some benefits of why API is so important to eCommerce sites today.


Security is enhanced when sites use APIs. Whenever you send a request, you aren’t directly linked to a server. You send small amounts of information, the API delivers it, and the server sends it back. This minimizes the risk of a breach or someone accessing the backend of a server.


Without APIs, you would have to call a store and ask them to look at their inventory from all their suppliers, which they would eventually get back to you. This, instead of having an API where you could easily see what a product was, the price, or its stock level.


APIs allow scalability and flexibility when expanding your store’s catalog, security, or data needs. Your store can grow at a faster rate when you don’t have to factor in new code for every single product or user.

What are some types of API used? 

There are 3 types of APIs used commonly today: 

  1. Open API
  2. Partner API
  3. Private API

Open APIs are publically available for anyone to use. BigCommerce, for example, uses roughly 25 different APIs, which are available for the public to use.

Partner APIs are designed by companies to offer API access to strategic business partners as an extra revenue channel for both parties. For example, Ticketmaster offers a Partner API to allow its clients the ability to reserve, buy, and retrieve ticket/event information.

Private APIs are not designed for public use and are designed for internal use. Let’s say you are traveling to a different city for a business meeting. You need to make a quick trip to the bank. You walk into “ABC Bank” and give the teller your account number. She quickly pulls up your account and you make a withdrawal. The teller was able to pull up your information by using ABC’s internal system, which uses an API to pull your account information and to update your new account balance.

Product information APIs

Product information APIs are on every eCommerce site, grabbing the information about your products and serving it to customers. 

Site search APIs

The ability to site search isn’t automatic. Site searches need APIs to search through all your products containing a certain query and retrieve it for your user. 

Payment APIs

If your online shop collects any form of electronic payments, you are using a payment API as the middleman between your shop and your processor.

Shipping APIs

Ever been to a site that asks you to put in your zip code to calculate shipping? That site is using an API with its shipping system or carrier to get you your best rate.

Currency conversion APIs

Buying shirts on a British site from a US IP used to be hard, now with currency conversion APIs, your favorite international stores can convert currency in an instant. This API opens hundreds of thousands of online shops to international customers. 

Why use a custom API solution?

Don’t get me wrong, already built integrations such as those available on the Apps marketplace are wonderful tools. However, there are times when a custom integration is simply better for business. Custom-built integrations offer one added bonus over pre-built apps, control. They are custom-tailored to your business’s specific needs. 


Created by

Abhiraj Bhowmick

I make stuff on the web and write blogs about it.







Related Articles