A Detailed Guide on API Development {2020}
mobile app development

API Development Best Practices (with an introduction for beginners)

APIs are the underrated intermediaries that make inter-app communication a lot easier.

API Development Best Practices (with an introduction for beginners)

You searched for a query on Google and thanks to our SEO practices, that got you to this page. Now you’re reading this blog. An act that took you a couple of seconds involved the following:

  • Google’s server request MobileAppDaily’s servers for information.
  • MAD sources the requested data and transmits it back to Google.
  • Eventually, you arrive on this page.  

Among all that goes on behind the laptop screen, perhaps what’s most intriguing is the interchange of information between Google and MobileAppdaily, or their servers.  

This is what Application Programming Interfaces (API) are for!  

When coders develop a website, they leave a set of instructions open-source. The point when another web-service (software that is hosted on an internet URL) tries to communicate with the first website, it does so with the assistance of this open-source code. In sophisticated terms, the codes are called applications, or in technical words an API. 

They let 2 disparate web services hosted on the world wide web, communicate with each other. You can call them intermediaries between two web services which come in different shapes and sizes processing client-server queries on:

  • Web-based systems
  • Database systems
  • Software Libraries
  • Operating Systems 
  • And Computer Hardware

Okay, so we’ve answered “how does an API work?”

But that’s just scratching the surface. It’s important you understand a few conceptual elements of APIs, without which their operability would stop dead in its tracks.

Basic Terminologies

API Key - Let’s call them a set of coded instructions passed into incoming API requests. It is their purpose to identify the origin and nature of the incoming request. They’re an inseparable part of the API architecture, required to block dubious sources accessing information from the web service. 

Endpoint -  Are referenced to pass a value in a given URL. 

JSON - The acronym stands for JavaScript Object Notion. This is a predefined format API development relies on for passing requests and sending responses between two apps.

GET - RESTful APIs use the same as an HTTP method to gather resources.

PUT - Again, an HTTP method of editing existing data. Development Agencies primarily engage it when they update a collection of information. For instance, a table.  

PATCH - Used when updating a single value. Such as a single entry in a table (in reference to the above example). 

POST -  interoperability is a two-way process. If an API has to collect information from an endpoint, it must be open to sharing data from its end. POST is an HTTP method for RESTful APIs to build (or add) such resources. 

DELETE - self-explanatory. 

JSON Web Token -  it is a standard used to create access tokens for an application.

API Throttling - this feature is a fundamental part of developing an API. It regulates the frequency of users accessing the API at a point in time. When site traffic increases beyond a threshold defined by developers, the 429 error is displayed which reads “Too many readers.”  
     
Rate Limiting - we’ve all faced situations while switching between applications/websites tabs when we are brandished a note which reads something like, “Our website has detected unusual traffic from your computer”. It’s’ nothing but the API limiting the rate of single-user access. 

Types of APIs

There are four major types of APIs:

1. Open APIs - public APIs are implied to be open for all. They hold no restrictions on access and are publicly available. 

2. Partner APIs - access to this category of APIs is extended through a licensure model. 

3. Internal APIs - they are custom-built for in-house enterprise channels. The organization tests the veracity of its services/products usually with such APIs. Jeff Bezos put a special impetus on the ingenuity of such innovations which allowed Amazon’s services to be interoperable and be offered as a suite via their business arm Amazon Web Services. 

4. Composite APIs - it differs from the categories above in that they are a sequence of processes triggered when a series of other tasks are executed. Note that above listed APIs are called to act upon the request of other APIs.

While the above categories broadly categorize and influence API development, there are also web service APIs we think readers should have an overview of:

1. SOAP - there has to be a set of messaging protocols for web services to interact with each other. Simple Object Access Protocol is a predefined set of rules which allows transmission of such messages. It uses Web Service definition language (WSDL) to publish details of its interface. It uses proprietary XML format message transfer.

2. REST - Representational State Transfer is a software architecture style used to define web services. They offer immense API development value as requesting codes can limit the scope of their request to specific data than point to an entire block of information. When incoming queries point to specific sets of information, it cuts short processing time. RESTful APIs are designed in conjunction with the REST protocol.
   
3. XML-RPC -  Unlike SOAP, here we use a specific XML format for data transfer. Its’ bandwidth consumption is relatively lower than other web service APIs along with it being easy to execute. Here’s an example:

4. JSON-RPC - it has multiple overlapping features with XML-RPC, however, it uses JSON to transfer data than XML. For instance,  

Prescribed Tools for API Development 

Developing an API could pose all sorts of challenges with even shorter turn-around time for those working in an Agile environment. So we thought we’d curate a list of most recommended software testing tools in the market for you. The vendors are merely listed, not ranked in any order. 

  • SoapUI - an open-source API development tool that facilitates testing both SOAP & RESTful APIs for use-cases like functionality, security, and performance. It runs on Java, making it easier for most operating systems to handle operations.     
  • Postman -  allows API development in addition to giving you a testing environment for the same using JavaScript. 
  • Katalon Studio - it provides an automation testing tool for mobile, API and web. Katalan deploys the BDD Cucumber framework that bridges the gap in internal communications between business stakeholders and I.T. teams. As a result of which, ongoing progress can be relayed to concerned delegates. DevOps tools such as Jenkins, Maven & Docker are easily integrable with Katalan. 
  • Apigee - it’s a cross-cloud API management platform, designed by Google Cloud, that allows you to pre-examine live session scenarios while working on proxy APIs. It offers end-to-end API management support and has been regaining top spot in Gartner’s Magic Quadrant report for the last 4 years. 
  • TestNG - it was inspired by JUnit & NUnit testing frameworks of Java offering unit testing and integration in API development. 
  • Rest Assured -  inspired by languages like Groovy & Ruby, this API testing tool is Java-based and predominantly for REST APIs. Key features include XPath validation, specification reuse, easy file uploads, and JSON path syntax. Web services based on XML, JSON, and HTTP can also be tested on Rest Assured.
  • Tricentis Tosca - DevOps environments have always posed challenges for software developers, especially for testing APIs. Tricentis has attempted to fill that void with a friendly user interface, aimed at beginners. 
  • Apiary - end-to-end design and development solutions facilitating mock environments for proxy testing. 
  • MuleSoft API - also known as AnyPoint API Manager, developers get a host of services to choose from. MuleSoft is especially popular in the programming community, as integration with leading cloud services like Salesforce and SAP is possible. Mule is the official run time engine for this platform.         

Must-have Features in an API Design 

Must-have Features in an API Design

1. Filtered Search

Triggers are implemented to source data from APIs. Post the first data synchronization, it is understood by all, there will be future changes. However, just as with any code, software developers need to be crystal clear about the who and why of changes, along with the trail of events. Records can be reconciled using timestamps, provided the API has built-in flexibility to execute filtered search criteria. 

2. Paging Sequencing & Sorting  

You now have a log of changes that are timestamped, but it’s part of the good coding practice to not flood the user with all changes at once. Paging has the ability to control both the volume and frequency of information a user gets access to, per session. There’s more, it can even display the remaining pages.

It’s all about optimizing the effectiveness of the API. 

End-users appreciate in-API functionality which enables sequencing pages by timestamped changes and other ad-hoc conditions.  

3. RESTful Support

It is common consensus within the software development community that the REST architecture outperforms SOAP. Hence, It comes as no surprise that RESTful APIs bag the best reception. 

But why? 

REST is an architectural style, unlike SOAP which is a standard. By virtue of this fact, RESTful APIs can be built on multiple standards like HTTP, JSON, URL and XML. On the other hand SOAP APIs are largely based on HTML & XML.  

4. Authorization via OAuth

the OAuth acronym stands for Open standard Authorization. 

Recall when you share your Facebook account information with third parties, do you also share your passwords? No. That’s because Facebook has backend OAuth feature sets that allow for such flexibilities while safeguarding privacy.  

This practice has become universal with API development for sharing user credentials with third parties. OAuth has come up with an update on OAuth 1.0, making OAuth 2.0 the preferred choice.   

5. Documentation

This one is down to common sense. 

Anything that is well documented makes it a preferred choice for reference, for projects whose foundation is built on prior implementations. Documentation tools such a Swagger allow you the ease of just recording the annotations used. It then returns the output to the user. 

But there are even times when only manual documentation will do. This practice is referred to as Mark-Down, and transpires when developers have no option but to record inputted commands themselves.  

API Development Best Practices 

Throttling

Break the term into two. The first word you get is throttle. It means to limit the supply of something, which is what the process is about. It helps to regulate and direct the total frequency of queries on the API. In fact, it is customizable to such extents, that we can limit the supply of people having access to the API as per days/weeks/months in advance. It is executed by the API manager, which further allows two types of customizability: 

Hard throttling - the total number of users will not exceed the pre-defined threshold. 

Soft throttling - people are notified if the API traffic is about to cross the pre-defined threshold. For instance, if the API can only accommodate a maximum of 100 users and the current traffic is 95, people will be notified of the same. 

Rate Limiting 

It can be used to limit the rate at which users actively access the API in addition the speed at which they can access it. API publishers, while uploading the APIs, assign multiple plans for subscribing licensees. As per the chosen model, B2B users can play around with live interactive sessions with the APIs. It’s calculated in real-time.

Automating Contingency Plans  

Stationing full-time employees for supervising data leaks from, say API servers, is a big NO. Human-error could prove costly in case there is a contingency the personnel is not trained for. Industry hotshots like Amazon Web Services have incumbent services like the Amazon Cloudwatch that automates such recurring status checks. You should have a checklist of alternatives to turn to in case such a disaster hits you.     

How does an API work?

General FAQ

  • What are API development Best Practices for RESTful APIs?
  • What is the difference between REST and SOAP?
  • How to design a good REST API?
  • What are the best API Development Tools?
Twinkle <span>Product Strategist</span>
Written By
Twinkle Product Strategist

Twinkle is an experienced business and marketing consultant of the mobile app industry. She advocates perfect branding to the latest tech releases. She is passionate about writing well-researched reports to help the app owners and the mobile app industry audience. Also, she has a vibrant touch that goes well in her writing as well.

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