How To Use An API (The Complete Guide) [Simple API Example]

15 Nov.,2022


What is an API and How Do They Work?

In the process of improving your applications, you will eventually come across a term like API.

API stands for Application Programming Interface.

It is impossible to imagine modern development without APIs. This term has many definitions, but we will try to explain it as simple as possible.

API is like an open language, the rules of which are shared by a certain service.

API is like an open language, the rules of which are shared by a certain service.

You can teach your application the rules of this language, so it can communicate with the service and access all the functions and data that the service is ready to share.

Speaking a little more formally, API is an interface that allows your application to interact with an external service using a simple set of commands.

You do not need to know the internal logic of the service, just send a simple command and the service will return the necessary data.

For example, if you need to contact the news aggregator API and get ten of today’s most popular news from it, you refer to the “topnews” command (which the service described in advance in the public domain), and in response, the service will send you the latest collection of sensations.

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Why are APIs important?

If there were no APIs, the functionality of your applications would be limited, and the development time would increase significantly since any function that is not implemented as a module of one of the programming languages would have to be developed independently.

APIs tie disparate applications together, allowing them to complement each other.

The hotel selection service uses an external API for recognizing and cataloging photos of rooms, the same service itself through the API provides an opportunity to select and book hotel rooms, thus enriching the functionality of many travel applications.

If there were no API, each application would be limited to a narrow list of its own functions without the possibility of expanding it to something that others have already invented and used for a long time.

Benefits of APIs

APIs allow you to save time when developing and help not to invent a bicycle.

It is much more efficient and more convenient to use the capabilities of one of the APIs than to try to independently implement similar functionality.

Moreover, it will be problematic to get some functions and data other than through the API (for example, a weather forecast, a thematic selection of news or a high-quality translation from almost any language).

APIs recharge your applications with the latest technology. With APIs, you can teach your application the latest image recognition and natural language processing methods.

Types of APIs

There are four main types of APIs:

  • Open APIs: Also known as Public APIs, there are no restrictions to access these types of APIs because they are publicly available.
  • Partner APIs: One needs specific rights or licenses in order to access this type of APIs because they are not available to the public.
  • Internal APIs: Also known as Private APIs, only internal systems expose this type of API, which is, therefore, less known and often meant to be used inside the company. The company uses this type of API among the different internal teams to be able to improve its products and services.
  • Composite APIs: This type of API combines different data and service APIs. It is a sequence of tasks that run synchronously as a result of the execution and not at the request of a task. Its main uses are to speed up the process of execution and improve the performance of the listeners in the web interfaces.

You can read more about API types here: Types of API

API Example

An API specification can take many forms, but often includes specifications for routines, data structures, object classes, variables, or remote calls. POSIX, Windows API and ASPI are examples of different forms of APIs. – Wikipedia


Endpoints are the key elements in the interaction of your application with the API. Usually, it is a specific address (for example,, by referring to which you get access to certain features/functions (in our case – a list of top news).

Commonly, the name (address) of the endpoint corresponds to the functionality it provides.

To learn more about endpoints, we will look at another example, this time within the RapidAPI service.

This service is an API Hub providing the ability to access thousands of different APIs.

Another advantage of RapidAPI is that you can access endpoints and test the work of the API directly in its section within the RapidAPI service.

You don’t need to immediately write a program or launch a Postman application to get an idea of the capabilities of the API.

Let’s take for example the Numbers API. This is a simple and free API providing interesting information about numbers and dates.

In order to find Numbers API section, enter its name in the search box in the RapidAPI service or go to the “Education” category from “All Categories” list and select this API from the list. Numbers API through RapidAPI is free, so you can use it freely as many times as you want.

Once you select Numbers API, the first page you’ll see is the API Endpoints subsection. This includes most of the information needed to get started. The API Endpoints subsection includes navigation, a list of endpoints, the documentation of the currently selected endpoint, and a code snippet (

Once you select, the first page you’ll see is the API Endpoints subsection. This includes most of the information needed to get started. The API Endpoints subsection includes navigation, a list of endpoints, the documentation of the currently selected endpoint, and a code snippet ( available in 8 different programming languages ) to help you get started with your code.

From the current subsection (Endpoints), we can test the API endpoint directly in the browser by changing the input for the endpoint. Once we make a request to the API by using the ‘Test Endpoint’ button, we will also see the response directly in the browser.

Let’s test Get math fact endpoint which provides a piece of interesting information about an arbitrary number. In this case, we are interested in the information about the number 42. Enter 42 in the only required parameter ‘number’ and click ‘Test Endpoint’ button.

We can see the JSON response from the API in the ‘Your Response’ tab, the Response Body block. In our case, it is the following:

"text":"a perfect score on the USA Math Olympiad (USAMO) and International Mathematical Olympiad (IMO)"

Congratulations! We made the first call to this API and got the first (probably) useful answer. It was not too difficult, right?

Request Methods

Having dealt with the basics of the API, let’s go a little further, namely, let’s deal with Request Methods, using which we can communicate with the API.

Without getting into too much detail, Request Methods characterize what action we are going to take by referring to the API. In total, there are four main types of actions:

  • GET: requests data from a server. This is the most common type of request. Using it we can get the data we are interested in from those that the API is ready to share.
  • POST: adds new data to the server. Using this type of request, you can, for example, add a new contact to CRM.
  • PUT: changes existing information. For example, using this type of request, it would be possible to change the color or value of an existing product.
  • DELETE: deletes existing information

How to start using an API?

  1. Get an API Key
  2. Test API Endpoints
  3. Create your first App

Now we can collect everything that we learned together and create a step-by-step guide on how to use the API. You can also watch the video below for a quick explanation.

1. Get an API key

An API Key is a unique string of letters and numbers. You will need to add an API key to each request so that the API can identify you. In order to get an API key, you need to somehow register with the API server and enter your identity data. On the example of RapidAPI – you can choose the method of registration that will be convenient for you. This can be a username, email, and password; Google, Facebook, or Github account.

2. Test API Endpoints

After we receive the API key, we can refer to the API endpoints (according to the rules in the documentation) to check if everything works as we expected. For this, we can use a REST client like Postman. In the case of RapidAPI, our life is much simpler. Immediately after registering with the RapidAPI service, we can go to the section of the API of our interest, subscribe to it, if necessary, then enter the necessary data directly on the API page and see the endpoint’s answer.

3. Create your first App

After we checked the endpoints and everything works as we expected, we can start creating the application, including calls to the necessary API. In this matter, RapidAPI can also simplify our lives. On the page of the API we need, we can use the Code Snippet block. We can choose your preferred programming language and immediately get the code that implements the task that we have just tested.

Code snippets are now available through RapidAPI for such programming languages as:

  • NodeJS
  • PHP
  • Python
  • Ruby
  • Objective-C
  • Java
  • and C#

(cURL & RapidQL snippets available as well).

Learn more at the RapidAPI Docs.

How to pull data from an API

Now, let’s go through the steps described above to take advantage of all the coolness of the Chuck Norris API, which is available through the RapidAPI.


1. Get an API key

Chuck Norris API is free, it does not require a special subscription so immediately after registering with the RapidAPI service we will receive the key. You can register by clicking on the ’Sign Up’ button in the RapidAPI menu.

As we already mentioned, you can register in any way convenient for you:

2. Test API Endpoints

Immediately after registration, you can go to the Chuck Norris API page. Enter the “Social” category “All Categories” list and select this API from the list.

For this example, we are interested in testing the /jokes/random endpoint, which gives a random joke about Chuck Norris. This endpoint has no required parameters, so just press the ‘Test Endpoint’ button and check the answer in the ‘Your Response’ tab, ’Response Body’ block.

Here is the JSON answer we received:

{7 items
"categories":[]0 items
"created_at":"2016-05-01 10:51:41.584544"
"updated_at":"2016-05-01 10:51:41.584544"
"value":"Chuck Norris ordered a chicken burger at In-N-Out and he got one."

Everything seems to be working properly. Now we can create an application.

3. Make your first app with API

Let’s use the Code Snippet block to get Python code that implements the functionality that we just tested. Add a print command to the snippet and we have a program ready that uses the coolest API so we can get outstanding advice from Chuck Norris for all occasions.

import unirest
response = unirest.get("",
   "X-RapidAPI-Host": "",
   "X-RapidAPI-Key": "4xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
   "accept": "application/json"

print response.body['value']

This is the wisdom from Chuck Norris we got this time:

Chuck Norris was briefly considered for the next Batman movie, but after test shoots, it became clear that it’s impossible to film the bat roundhouse kick and survive.


APIs are an integral part of the modern development ecosystem. Having spent a relatively short period of time studying them, you can use them to widely extend the capabilities of your own application.

Ready to get started? Click “Browse APIs” to search through 1000s of RESTful APIs available for API integration into your website or app.

Additional Reading

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FAQ About RapidAPI

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What is RapidAPI

RapidAPI is the world’s largest API marketplace with over 500,000 developers and 8,000 APIs. Discover, evaluate, and integrate with any API using a single account.

How Do I Reset a Compromised API Key?

To reset your API key, you will need to delete the application associated with compromised API Key. To do this, head over to your developer dashboard at On the left-hand side, select the ‘My Apps’ button. From there, select the pencil for the Application/API key you would like reset and press the ‘Delete’ button when it appears. After deleting the application, you can add a new application to generate a new app/API key for your account.

How to Change My Credit Card?

There are many reasons why you might want to change your credit card on RapidAPI. To do this, you can go to your billing dashboard at There you will find your current credit card information as well as a way to edit or delete your credit card.

Deleting Your Credit Card

In order to delete your credit card, you must first unsubscribe from all the APIs your account was using.

What If My Credit Card Is Declined?

Sometimes depending on the bank’s fraud protection settings, a bank will decline the validation charge we make when we attempt to be sure a card is valid. We recommend first contacting your bank to see if they are blocking our charges. For more help around this issue, please contact and our team will investigate further.

Does an API have _______ Functionality?

With so many APIs available on RapidAPI, created by thousands of different API providers, there is a lot of different API functionality you can find. The two biggest recommendations we have for seeing what data and functionality an API has:

    1. Contact the API Provider to ask them directly. API providers are the best resource of knowledge for their API, so you can contact them through the ‘Discussions’ tab of the API.
    2. Test out the API yourself before subscribing to a paid plan. Many APIs will have a free BASIC plan associated with their API. What these free plans allow is for you to make a few calls to see exactly what data and functionality an API provides before committing to a paid pricing plan.

What Should I Do If I’ve Found an API That Is Fraudulent or Falsely Advertising What It Provides?

Our entire team wants to ensure you have the best experience possible while using RapidAPI. Unfortunately, there can be times when an API provider has listed an API that does not provide the functionality advertised. If you see different results or data than what the API is advertising, please contact

When Does the Daily Pricing Quota Window Reset?

RapidAPI provides a lot of customization for how API providers set up their pricing, one of these options is the ability to set a daily quota limit. The daily quota period starts at your time of subscription and ends 24 hours from that time. For instance, if you subscribed to an API at 11:30:15 UTC on June 2, your daily quota will reset at 11:30:15 each day.

Where can I find the exact subscription start time?

By going to your billing dashboard, then transaction history, you’ll see a list of your invoices. Opening one of your invoices will show the exact time of subscription.

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