A Detailed Guide on API Development for Mobile Apps

Updated 19 Apr 2024
Published 28 Oct 2020
Rahul Mathur 3234 Views
A Detailed Guide on API Development For Mobile Apps

The evolution of technology has changed our lives in the last decade like never before. We can observe the gradual change in every walk of life; our lives have become easy, and we can use various kinds of gadgets that can perform the desired functions for us.

Though we have many other influential technologies, mobile technology has changed the technology paradigm in a way that was never envisioned a few years ago.

Its influence can be understood by the fact that there are more than 2 billion smartphones now and this count has been changing like wildfire.

This huge number of mobile devices, along with emerging technologies like AI, ML and the Internet of Things, are dramatically revolutionizing the entire mobile industry.

Every smartphone needs an application so that it’s end user can utilize its capabilities; thus, mobile application development has become a hot cake and a multi-billion dollar industry, where hundreds of tech organizations are developing different kinds of applications and striving hard to deliver a better mobile experience to the end users.

When we talk about mobile app development, we also hear a buzzword: API. In this article, we will discuss the various aspects of APIs and their usage in mobile application development.

What is an API?

API is an Application Programming Interface, which is a link between the two software applications and allows the applications to interact with each other.

Whenever we use any application on our mobile devices, it sends and receives data to and from a remote server via the Internet.

At the server’s end, the application retrieves the data, interprets it, processes the required actions and sends it back to your phone.

The application on our mobile phones then interprets the incoming data and displays it to us in human-readable format.

api development for mobile apps

Mobile applications like Twitter, Facebook, Instagram, and many more are using APIs to send messages.

For example, if we are using different applications on our mobile phone, the application connects to the internet and sends data to the server.

The server retrieves that data, interprets it, performs the actions and sends it back to the phone.

To make it more understandable, let us discuss other examples:

1. When we are ordering food online through Zomato, Swiggy, etc., there are multiple options to choose from, including vegetarian and non-vegetarian options, cooking instructions, packaging instructions, and quantity. To order the food, we interact with the restaurant website to access their database to check the availability of food items.

2. Whenever we want to check the weather, we usually use Google search or Apple’s weather app. These applications help us search the weather-related information on Google and populate the current weather conditions and forecast for a specific location.

As we know, Google is not in the weather forecasting business; hence, they have to source this information from a third party. They obtain this weather-related information through an API developed by that 3rd party organization.

3. Another famous API usage is the social media log in facility on different websites and platforms. We usually get the “log-in using Google, Twitter or Facebook” option to login to websites without creating a separate user profile. This is indeed a function of an API, which keeps track of our social media accounts and enables quick login for users.

Instead of logging-in to the user’s social media accounts, applications with this functionality use APIs to authenticate the user with each login.

4. Whenever we make any online payment using PayPal, it offers functionality that ensures that only limited information is required without exposing the sensitive data of the end user or gaining unintended permissions.

When we click on the “Pay with PayPal” button, the marketplace application transmits an order to the PayPal API. This order contains information about the amount owed, other payment and item-related details. A pop-up authenticates the user, confirms their purchase and processes the order.

5. Have you ever thought that travel booking sites aggregate thousands of flights and destinations and show the cheapest option? The answer is through third-party APIs to collect flight and hotel availability from providers.

It makes the process fast and automated; otherwise, without using an API, the booking process becomes manual and takes a lot of time to check availability and book.

Today, the “API economy” is quickly changing how people interact, from online shopping, hiring cabs to photo sharing All this happens through API. Technical innovation is happening at a faster pace because of the API.

Without APIs, the applications get disconnected and confusing. APIs can also be useful internally for a company, in addition to sharing resources across companies. Instead of having duplicate code for each of the other apps, they can share data through one API.

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Benefits of Using an API

1. Application service and delivery:

As an API has direct access to the app components, the delivery of information and services is more flexible, and it is easy to manage the application.

2. Better Efficiency :

An API can ensure the availability of content across all channels and it offers the flexibility to distribute it in an efficient manner.

3. Automation:

API offers high degree of automation, where it gives facility to update the workflows and make them rapid, cost effective and more productive.

4. Integration:

APIs allow seamless integration of content from any application or site. This guarantees a more highly integrated user experience and fluid information delivery.

5. Personalization:

APIs allow developers and organizations to customize the content and code as per their requirements, giving them the freedom to make any sort of change to their product.

6. Service Provision and Adaptation:

Any application or service needs provisioning or changes over time, and APIs come to the rescue as they help us anticipate the changes. API makes provisioning more flexible and it supports data migration in a better manner.

Types of API’s

There are four types of APIs:

Open APIs:

These are also known as public APIs, due to their public availability. These API’s are available to all without any sort of restriction.

Partner APIs:

For using such APIs, software firms or developers need specific rights and licenses to access such types of APIs, as these are not available to the public.

Internal APIs: 

These are also known as private APIs due to their limited scope of usage. These API’s are developed for internal use within an enterprise, and exposure of such API’s are limited to Enterprise’s internal systems only. An Enterprise can utilize such APIs to its services, products, and end-user experiences.

Composite APIs:

These APIs amalgamate different kind of data APIs and services. Such API’s offer ability to speed up the execution process and enhance the performance of web interface listeners.

Also read: How Does the Fintech and Banking Sector Use APIs?

Web Services APIs vs Mobile APIs

Web Service APIs:

1. Simple Object Access Protocol (SOAP):

This protocol utilizes XML as a format to execute the transfer of data. Its primary function is to develop the structure of methods and messages of communication. It uses WSDL (Web Service Definition Language) to display the definition of its interface.

2. XML-Remote Procedure Call:

This API uses a specific XML format to transfer the data over the network, rather than the proprietary XML format used by SOAP. It is older and simpler than SOAP and it utilizes less bandwidth for communication.

3. JSON-Remote Procedure Call:

It has lot of similarity with XML-RPC; however, it uses JSON format to transfer the data instead of XML format.

4. Representational State Transfer (REST):

It is an architectural principle rather than a protocol, like its competitors.

API for Mobile Apps

One of the most used mobile app ecosystems is Facebook, which offers different kind of APIs to perform different kind of functions. If you want to shop online using a mobile app, then the app could use the PayPal API or any other API that may allow us to make payments easily.

In layman terms, we can say that API development for mobile applications allows end users to interact with other applications and offers a superior mobile app experience. All we need is the integration of APIs with our mobile app, rather than developing additional features.

iOS Rest API

A Rest API is an API that uses HTTP requests while managing and handling the data. It uses functions to PUT, GET, Delete or POST the data.

REST is the most used style for designing APIs, especially in the mobile world. It is a de-facto choice for building the APIs, which enable users to connect and interact with cloud services and utilized by sites such as Amazon, Google, and Twitter.

There are a few things which need our attention:

  1. We need to have a better understanding of web services. The web services are built upon REST architecture that returns data in JSON format.
  2. We must have in-depth understanding of the function of HTTP protocol. The REST APIs depend on the HTTP protocol for managing and handling the data. One should be familiar with the way HTTP uses URLs, transfers data, and expresses remote actions.
  3. Every RESTful API offers different URLs to transmit the data; hence, it is very much required to map the URL’s to make requests work efficiently.

Should we Build or Buy an API?

There are two choices you can make when developing, you can build yourself or you can buy by integrating with an already existing API.

Buying an API is the easiest and quickest option, as It saves time and make money and requires less development efforts of developers, as we do not have to develop an API from scratch.

Building an API requires more developer expertise and experience since this is a complex process; hence, using an already existing app is much easier.

Build or Buy an API

Some renowned websites, like RapidAPI, offer customers to discover, assess, and buy existing APIs. It is recommended to search and try the API’s available first, so that we will not be putting the efforts to reinvent.

There are a lot of APIs available on the market, both paid and free, that can be easily integrated into mobile applications.

Let us take an example: Uber makes use of third-party APIs for their mobile app, Multiple APIs works together to enhance the fundamental features of the application, like messaging, database drivers, usage of GPS data, etc.

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Things we need to keep in mind while building an API

Common Architecture

If we are developing our own API, then the best option is “common architecture,” which is the baseline for API which most experienced developers use. The four different types of common architecture are:

  1. Pragmatic REST: It is perfect for both mobile and web applications.
  2. Web service
  3. Event-driven
  4. Hypermedia

The most commonly used architectures for mobile app development are Pragmatic REST and Event-driven. Hypermedia is mostly used with web applications; however, most developers are not familiar with this design. On the other hand, the Web service is not known for mobile apps optimization.

Apps for instant messages, games for multiple players, and video chat applications are all suitable for event-driven architecture.

Storage and Database decisions

While developing an API, it is extremely important to make the decision to choose the right Database and Storage for that.

The type of database we may use is not that important, however, the usage of entity ID is quite important, we must use randomly generated UUIDs instead of sequential UUIDs. This helps secure the resources by making IDs much more difficult to predict.

When it comes to selecting the right database to store the data, we may consider a relational database like MariaDB or MySQL. We may use MongoDB Database if our requirement is to use a NoSQL database.

Sometimes we may have to use a hybrid database that offers both relational storage and document storage support. The database you use depends on the kind of data you may be using.


  1. It is highly reliable and stable.
  2. Data is well structured, rigid, and defined; hence, it encounters fewer data mismatch bugs.
  3. There are lots of libraries, frameworks, and tools to leverage.
  4. Scaling requires extensive domain knowledge.


  1. It has no tables, no non-relational structure and no schema.
  2. It offers better scaling capabilities than traditional SQL-based databases.


  1. Flexible: mix relational data with model-independent data.
  2. It offers additional features and tools for Database administrators.

Cloud Document Storage

Cost effective solutions like Amazon S3 Buckets could be used, which helps us storing huge sets of whole documents.

Documenting the API Process

It is always recommended to document the process of developing an API and keep track of all the efforts we have put in. Having clear documents will help us maintain the history and current state of the API, making future updates easier.

This process helps us while distributing the API on Marketplace, as it facilitates other mobile applications to make use of your API, and it also acts as a reference document for the developers who will work to integrate your API with their respective applications and codes.


If you are building your API or using a third-party API, security plays a crucial role in mobile app development. An API will face access control mechanisms, secret keys, and privacy controls that keep the backend system and data secure.

Security is a paramount concern and necessity in today’s tech world when it comes to confidential and sensitive data and high value monetary transactions.

Earlier, APIs used to have their own customized security protocols and controls, which used to be a little bit complex, however, currently, we have standards like TLS, Open ID connect and OAuth2 that help us simplify the entire process.



It is an authorization framework that works by granting applications limited access to the user accounts on HTTP services such as Facebook and Google.

Here, user authentication is assigned to the service that hosts the account information and allows account access by third-party applications.


It is known as the Transport Layer Security Protocol, which is a cryptographic protocol that facilitates end-to-end communications security over data networks. It is also used for securing enterprise communications and online monetary transactions.

Open ID Connect:

This acts as a simple layer that works on top of an OAuth2 protocol. It helps clients validate an end user’s identity and profile information, which is based on thorough authentication conducted by a dedicated authorization server.

Open ID Connect helps web-based and mobile clients receive and request the necessary information about users and their authenticated sessions.

Implementing RESTful API

  1. The biggest decisions when implementing RESTful API is the location for your server hosting. You can host your server, or you can use server cloud hosting.
  2. It is important to protect your RESTful API system with encryption, monitoring, and automated backups.
    OAuth2.0 is known as one of the most secure ways to protect your RESTful API. It is much safer and easier to just use existing methods, such as OAuth2.0.
  3. This is to make sure that all your passwords and other sensitive data do not get stored in plain text. Always encrypt this information.
  4. When implementing the RESTful API, one question should come to mind: the cost based on your usage. How much will it increase when the usage goes up?

Some features, like development, production, and staging, could potentially let you set multiple environments. Using the correct tool can help us implement the RESTful API in easier manner.

Tools which help with RESTful API

1. Slate:

It has a simple design. Slate helps you create beautiful, intelligent, and responsive API documentation. You can use GitHub as a host for this tool.

With slate, everything gets written in Markdown, so it is easy for developers to understand and edit. You can write code in multiple languages and everything on the same page.
To use the slate, you need:

  • Ruby (version2.3.1 or newer)
  • OS X or Linux
  • Bundler

2. Apiary:

The Apiary blueprint is open source. It focuses on design components. You must have a plain text editor before you can start using Apiary. It is recommended to switch the syntax to Markdown for a more enhanced experience.

3. Swagger:

It also has an Open-source Tool. It allows you to create a RESTful API with a stabilized workflow, and you will benefit from automated updates. Their libraries have server templates the most popular coding languages with plugins.

Best Practices to use API for rapid App Development

We need to envision the end-product and must invest in the stack and other technical resources to create highly responsive and interactive digital experiences for end users.

People usually make modifications and develop their existing applications to make them efficient and fast, but if they have slow APIs, the end user may face a poor experience.

We must ensure the reduction of API calls and network chatter, that are responsible for draining the battery of the mobile device.

Mobile applications are developed in such a way that they must make multiple service calls to execute a transaction on a specific screen.

While developing a front-end API, we must ensure that it executes a single API call per screen, as a greater number of service calls may result in low responsiveness, poor performance and a drastic drain on the battery.

Move points of integration from large systems to a microservices architecture to meet the burgeoning demands for new digital experiences.

As enterprises invested in APIs, the high demand and the need for scalability created the need to break up the large system into small services.

This is called a micro-service. Micro-service architecture produces a decoupled API that is simpler to create, implement, maintain, and consume

We must use API management tools and coupled with the above best practices, it will offer exceptional digital services for end users.

The constant collaboration between developers working on the client apps and backend ensures continual progress is achieved. The less time we spend guessing how APIs work in every situation, the more time we spend building out the features that make our apps unique.


APIs are indeed an integral part of mobile application development ecosystem. We can use them to widely extend the capabilities of an existing mobile application to a great extent.

APIs provide developers with seamless flexibility and the opportunity to innovate. It is very much understood that without APIs, communication between apps would be suffocated and developers would be re-writing the code that performed the same functionality.

APIs are used not only for simple functions like sharing photos with friends but also for performing complex operations and real-time functions.

As the world moves ahead with the technical revolution, APIs will play a bigger role in powering and equipping the mobile apps and websites we use every day.

Rahul Mathur

Rahul Mathur is the founder and managing director of ARKA Softwares, a company renowned for its outstanding mobile app development and web development solutions. Delivering high-end modern solutions all over the globe, Rahul takes pleasure in sharing his experiences and views on the latest technological trends.

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