A Complete Guide to API Development

June 2, 2022

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You must have come across the term API, irrespective of whether you are a tech geek or not. API stands for Application Programming Interface. They are used to let other applications use the data, features, and services of a particular application. In simple words, API acts as a communicating link between two applications.

Let’s take a look at an example to understand API better. Familiar with the ‘Connect with Facebook’ button on various websites and apps for login purposes? When you click it, you don’t have to enter your Facebook credentials. Your login details are entered automatically by accessing your data stored on the Facebook servers. This is all done thanks to an API.

APIs have turned out to be a boon for developers across the globe. API development tools have significantly simplified their lives. They no longer have to write the application code from scratch. Rather, they can make use of an API to enable seamless communication and data sharing between applications.

Now that you have a basic understanding of API, let’s look in detail at how an API works.

How does an API work?

Let’s consider the example mentioned earlier. Suppose you need to log in to the Candy Crush game with your Facebook account to save and sync your game progress. You click on the ‘Connect with Facebook’ button within the game. When you do that, a request is sent to Facebook to access the database and get the relevant data. When the login data is retrieved successfully, the data between the two platforms can be connected and exchanged henceforth.

When talking about data communication between two applications, API works majorly in two ways: REST and SOAP. Let’s take a look at each method to understand them better.


REST stands for Representational State Transfer. It is a programming architectural implementation that is aimed at enhancing the communication between two applications. It makes particular data available only when requested by sharing references. It does not copy the entire data itself. The systems that make use of REST architecture are called ‘RESTful’ systems. The most common and biggest example of a RESTful system is the World Wide Web.

Developers can use Rest API development tools to build, test, manage, and deploy RESTful APIs. These tools help developers with web API development as well as mobile API development based on REST architecture. Some of the commonly used REST API development tools include:

  • Amazon AWS Free Tier and Amazon API Gateway

  • IBM cloud API management

  • Runscope

  • APImetrics

  • JSONStub


SOAP stands for Simple Object Access Protocol. The protocol enables applications and processes using different operating systems to communicate with each other via HTTP and its XML.

SOAP-based APIs are developed for multiple purposes, such as creating, updating, and deleting data such as usernames, passwords, and custom objects.

SOAP API requires explicitly defining every operation the particular service provides. Moreover, the XML structure of the response and request for the particular operation needs to be defined too.

Both SOAP and REST are highly helpful in mobile API development and web API development. However, many developers prefer using REST over SOAP. REST is lightweight and platform-independent, which makes it the preferred API choice for developers.

What are the types of APIs?

There are different types of APIs that developers can use depending upon the purpose. APIs can be classified mainly into four main categories. They are:

  • Open API

  • Partner API

  • Internal API

  • Composite API

Let us take a look at each

  • Open API

    These APIs are available publicly for everyone to use. They provide developers programmatic access to proprietary software.

  • Partner API

    Unlike Open API, they are accessible to specific developers or businesses only. The entitled developer or business needs to follow a proper onboarding process to get access to such APIs.

  • Internal API

    Internal APIs are restricted for internal team usage only. They are not exposed to external users, developers, and businesses.

  • Composite API

    Composite APIs are a combination of multiple services and data APIs. They combine different service and data APIs.

Now, we move to the meat of the article. We will take a look at how to build an API, the API development life cycle, the API development tools, and other aspects related to API development.

How to build an API?

The process of building an API is similar to creating any other software. The API development life cycle can be broadly divided into four main stages. They are:

  • Determining the requirements of the API

    The first thing you need to do is determine your API requirements. These include the functional as well as non-functional requirements of the API. To understand your requirements, ask yourself the following questions, “Who is the target audience?” “How to incorporate the target audience’s needs into the API?” and “What are the expectations from the API in terms of performance, usability, security, and response time?”

    Once you have the answers to the questions and have clearly understood your functional and non-functional requirements, you can move to the next step – designing the API.

  • Designing and developing the API

    In this stage, you need to design the API as per the decided requirements. You will then need to develop the API based on the design finalized during the requirements stage. During the API designing and development process, you need to consider the following:

    1. Providing the API with a meaningful name and a simple and useful description.

    2. Defining the API operations.

    3. Specifying the data models.

    The quickest and easiest way to develop an API is to use API development tools. There are a plethora of tools available for developers to create an API. Some of the popular API development tools are Apigee, APIMatic, API Science, ClearBlade, Postman, and Swagger. You can choose a development tool of your choice to develop your API.

    Once you have completed the designing and development stage, you can proceed to the testing stage.

  • Testing the API

    Once the API has been developed, you need to ensure that everything works exactly as planned. Hence, you need to test your API under different test environments. API testing also helps check the security of the API, ensuring safety against a potential hack in the future.

    You can use automated or manual testing methods to test the functionality and security of the API.

    API testing can turn out to be a lengthy process if the developed API has functional and security issues.

  • Deploying or publishing the API

    Once you have tested the API and found everything to be in order, you can deploy or publish the API. This makes the API available for use for the intended target audience.

    After you publish the API, you need to constantly monitor it. You need to see how the API is being used and how it performs in a real environment. You need to monitor the following metrics to ensure that the API is working as intended:

    1. Operational metrics

      These include the availability and the output of the API.

    2. API metrics

      This includes API engagement and consumption.

    3. Business metrics

      This includes how the API is affecting business operations.

Now that you’ve understood how to build an API and the API development life cycle, let’s take a look at some of the best practices you need to follow during the API building process.

What are the best practices to follow during API building?

To ensure that the API development process is carried out smoothly and efficiently, developers need to follow the practices mentioned during the API building process.

  1. 1. Use Throttling

    This method is best for protecting the API from DDoS attacks as it helps redirect the flow of traffic.

  2. 2. Consider the API gateway as an enforcer

    The API gateway must be considered as an enforcer while setting up throttling rules. This is essential to ensure that only authorized users get access to the API data.

  3. 3. Allow overriding HTTP method

    You need to allow overriding the HTTP method with the RESTful API as some proxies only support GET and POST methods. You will need to employ the custom HTTP Header X-HTTP-Method-Override.

  4. 4. Evaluate the APIs and infrastructure

    To prevent the API from memory leaks, CPU drainage, and other issues in real-time, it is essential to evaluate the API and the infrastructure. You can do this using various evaluation tools available in the market.

  5. 5. Ensure security

    You need to ensure that the API is secure as well as user-friendly. The user should not spend more than five minutes for API authentication. Otherwise, it proves that the API is not user-friendly. Similarly, the API should be able to withstand cyberattacks and protect critical data. Developers can use token-based authentication methods to make the API secure.

  6. 6. Documentation

    Lastly, you will need to create detailed and accurate documentation for your API. This will help reduce the project implementation time and cost, which will prove highly beneficial for your business.

    Now, let’s turn our focus to the must-have API features. This will help accelerate the API development process while ensuring its efficacy and efficiency.

What are some of the must-have features for an API?

When developing an API, you need to ensure that the API has certain features that will ensure the smooth functioning of the API after it reaches the deployment stage. Some of the essential or must-have features of an API are:

1. Authentication and authorization

Authentication means verifying the identity of the individual trying to access the API. In simple words, it is similar to passwords, fingerprints, and face recognition that identifies and authenticates users before granting them access.

Authorization, on the other hand, means deciding whether a verified individual has permission to perform a particular action. For example, a particular member of the development team might have the authorization to view a resource. They, however, might not be authorized to create a new resource.

2. Cache Strategy

Developing a good cache strategy helps in the quick retrieval of resources. You can use tools like Memcached and Redis for caching purposes.

3. Error handling

Ensuring good error handling is necessary to simplify the debugging process. Developers can easily find out the cause of the error, whether it is client or server-based. For certain errors, the client can make changes to the request to correct them. However, for some errors, they might need to contact customer support. Some methods that can help with error handling include:

  • Using standard codes

  • Compiling the correct number of errors

  • Explaining the cause

  • Separating the different types of errors

4. API testing

As mentioned earlier, API testing is important in the API development life cycle. It helps find issues with the API security and functionality before the deployment stage.

5. Wrappers

Wrappers combine various sets of API calls into user-friendly actions. User interaction is not needed with a wrapper.


We hope that this blog helped you understand the various facets of API development. APIs have truly proven to be a lifesaver for development teams across the globe. They have reduced the amount of work required involved and provided an easy and quick way for applications to communicate with each other.

If you are looking for API development, you can reach out to our experts for API development services. Our experienced and robust team will help you build a secure, reliable, and functional API at competitive rates. Get in touch with us today.

About the Author Ranjit Singh is the Chief Executive Officer (CEO) at RV Technologies. In the past 10+ years, he has focused on helping clients to expand their business through the best digital solutions. Leading a team of 100+ employees, he knows how to implement the best market practices to transform a client’s business growth and help him achieve dedicated goals.

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