This is a guest post written by Subho Halder, co-founder and chief information security officer at Appknox.
Applications these days are witnessing a meteoric rise in the number of functionalities and microservices. And with this rush to add more and more functionalities and build more applications at an unprecedented rate, the dependence on APIs (application programming interfaces) has also skyrocketed. This beginner’s guide to APIs covers API basics, such as common types of web-based APIs and the future of APIs.
Related: What is an API?
First of all, what is an API? An API is an intermediate software agent that allows dependent applications to communicate with each other. APIs provide a set of protocols, routines, and developer tools enabling software developers to extract and share information and let applications interact in an accessible manner.
Be it web APIs that connect web applications to other platforms or APIs used by IoT devices to collect and process data, the use of APIs has expanded like never before.
One prominent example of the APIs which we encounter in our day-to-day life is the “log in to your account with Google/Facebook/Twitter” functionality that you may find on several internet platforms. These APIs let the host application interact with the user’s social media account and make the login process much easier than before.
Types of web-based APIs
APIs come in many types and forms. Which one a developer chooses among a variety of API protocols and standards depends on the purpose. The common API types include:
REST-based APIs
A data-driven architectural style of API development, REST (Representational State Transfer) is one of the most lucrative categories of web-based APIs. Based on Uniform Resource Identifiers (URIs) and HTTP protocol, REST-based APIs use JSON for data formatting which is considered to be browser-compatible.
REST-based APIs are extremely simple when it comes to building and scaling as compared to other types of APIs. When these types of APIs are put to action, they help facilitate client-server communications with ease and smoothness. Because REST-based APIs are simple, they can be the perfect APIs for beginners.
As compared to its peers, SOAP-based APIs (Simple Object Access Protocol) can be viewed as quite complex in terms of use. These APIs use a type of protocol known as Simple Object Access Protocol, which is a common communication protocol. This helps them in providing higher levels of security and makes them better at accuracy as compared with the REST-based APIs in the way messages are exchanged.
GraphQL-based APIs
GraphQL is one of the most advanced sets of web-based APIs where open-source data query and manipulation language is used. This makes it easier for forming a definitive pathway for the runtime that plays a vital role in fulfilling queries with the pre-existing data.
Although it is well known that GraphQL and REST APIs both use the same set of APIs, the major thing that differentiates them is the interface: a single interface-id is put to use by GraphQL when it comes to organizing data into the format of a graph.
Related: The future of GraphQL
XML-RPC
XML-RPC (Extensible Markup Language-Remote Procedure Call) can be described as another type of API protocol, which differentiates itself in terms of information security and the use of XML format that is specifically designed for transferring data. When compared to SOAP-based APIs, the XML-RPC protocols are easier and much simpler to use since they use minimum bandwidth.
WebSocket
A two-way interactive communication session between the user’s browser and a server can be made smoother and faster with the help of an organized set of APIs known as WebSockets. WebSocket APIs play a vital role in helping receive event-driven responses, and they also help in easier management of sending messages to a server. Plus, the entire process involving this doesn’t even require having to poll the server in order to receive a reply.
Instead of focusing on isolated programs and applications, organizations are now shifting their focus towards building scalable and interactive solutions with the help of APIs. They have become an essential part of all the applications that we see today. Because of their widespread capabilities, APIs can make development faster, increase customer reach, enhance business value, and also reduce time-to-market without hampering the quality of the final product. Based on these facts, it’s safe to assume that the API-centered development approach will continue to grow and prosper in the upcoming future.
Technical review by Kin Lane.
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Postman provides a wide range of functions and features to assist with API development, testing, and collaboration. Here are some commonly used functions in Postman:
Creating and Managing Requests: Postman allows you to create API requests by specifying the request method, URL, headers, parameters, and body. You can manage and organize requests within collections, including creating folders, adding descriptions, and reordering requests.
Request and Response Visualization: Postman provides a user-friendly interface to view and analyze request and response data. It supports syntax highlighting for various data formats such as JSON, XML, and HTML, making it easier to understand and validate the data.
Environment and Variables: Postman allows you to define variables and environments. Variables enable you to store and reuse dynamic values across requests, making them flexible and easy to maintain. Environments provide sets of variables specific to different environments (e.g., development, staging, production).
Tests and Assertions: Postman supports writing test scripts using JavaScript for automated API testing. You can write assertions to validate response status codes, headers, response bodies, and more. Postman's testing framework allows you to assert and validate different aspects of API responses.
Pre-request Scripts: Postman enables you to execute scripts before sending API requests using pre-request scripts. These scripts can be used to dynamically generate values, manipulate data, or set variables based on specific conditions.
Collection Runner: The Collection Runner allows you to execute a series of requests in a collection. It enables you to perform data-driven testing by iterating over multiple sets of data or environments. You can configure iterations, delays, and data sources for more comprehensive testing.
Mock Servers: Postman allows you to create mock servers for simulating API responses without a live backend. Mock servers are useful during development, allowing frontend developers to work independently by providing simulated API responses.
Documentation Generation: Postman can automatically generate documentation for your APIs based on your requests and collections. It provides a simple way to share API specifications and details with stakeholders.
Collaboration and Teamwork: Postman offers collaboration features such as sharing collections, collaborating on requests, and commenting on specific requests or collections. It also supports version control integration to manage changes and updates effectively.
Integration and Automation: Postman integrates with various tools and services, including version control systems (e.g., Git), CI/CD platforms (e.g., Jenkins), and API management solutions. It provides options for integrating with these tools to automate API testing and deployment processes.
