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What is the difference between an API, a web service, and a microservice?

Can anyone tell me What is the difference between an API, a web service, and a microservice.

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Posted 2 months ago


What is an API?

APIs are building blocks of online connectivity. They are a medium for multiple applications, data and devices to interact with each other. Simply put, an API is a messenger that takes request and tells the system what you want to do and then returns the response back to the user. A documentation is drafted for every API, including specifications regarding the manner in which the information gets transferred between two systems.

What are Web Services?

A web service can be any piece of software that uses a standardized XML messaging system & is available online over the internet. XML stands for eXtensible Markup Language & is used to encode all communications to a web service. For example, a client invokes a web service by sending an XML message, then waits for a corresponding XML response.

What is a microservice?

A collection of focused and small services which, on execution develops a complete application. A single responsibility of the application which you are developing is represented by an instance of a microservice. A microservice is a self-accommodating process that runs a unique business capability.

Now that you know the difference between what they do, let's have a look at why are they important.

Importance of API

APIs can interact with third-party application publicly. Ultimately, upscaling the reach of an organization’s business. So when we book a ticket via, we fill in details regarding the movie we plan to watch.

  • Movie Name
  • Locality
  • 3D/2D
  • Language

These details are fetched by API and are then taken to servers associated different movie theatres to bring back the collected response from multiple third-party servers. Providing the user with the convenience of choosing which theatre fits best? This is how different applications interact with each other.

Instead of making a large application and then adding more functionalities via code in it. The present times demand Micro Service Architecture wherein we create multiple individually focused modules with well-defined interfaces and then combine them together to make a scalable, testable product. The product or software which might have taken a year to deliver can now be delivered in weeks with the help of Micro Service Architecture.

  • API serves as a necessity for Micro Service Architecture. Consider an application which delivers music, shopping & bill payments service to end users under a single hood. The user needs to login to the app and selects the service for consumption. API is needed for collaborating different services for such application, contributing to overall enhanced UX.

  • API also enables an extra layer of security to the data. Neither the user’s data is overexposed to server nor the server data is overexposed to a user. Say in case of movies, API tells the server, what user would like to watch and then tells the user what they have to give, in order to redeem the service. Ultimately, you get to watch your movie and the service provider is credited accordingly.

Importance of Web Service

There are 2 different type of Web Services: - SOAP and REST

Advantages of REST web services

  • REST architectural pattern is basically lightweight in nature. So, when you have bandwidth constraints then prefer REST web service.
  • Easy and fast to develop. Also, adapted by most social networking sites.
  • Mobile App development growing rapidly and for their server interaction, it uses this REST pattern as it is faster in processing request/response data.

Advantages of SOAP web services

  • Web service is self-describing using WSDL
  • Communicates using open protocols such as SOAP/HTTP.
  • Loosely coupled as these interactions are platform-independent and language-independent.
  • Schema (XSD) can be used to describe request/response message pattern.

Importance of Microservices

  • Modifications are done easy - With businesses expanding modifications comes as a part of life for a software developer. Microservices creates a loosely coupled system. So if we ever want to rebuild, upgrade or replace a microservice then we don’t have to rebuild the complete application, simply rebuilding that particular MS will do just fine. This is very useful in the gigantic enterprise system. Also, we can perform a modification on a microservice by simple disabling that microservice and not the entire system.

  • Data Security - Each MS helps to a establish a single business capability and has its own separate data storage. For example, a customer registration page. This prevents from entire database corruption.

  • Flexibility - Can be written in different code languages.

  • Stateless Communication - Each request and the respective response establishes independent transactions helping you to scale effortlessly.

  • Prevents from a complete shutdown - If one of your microservice goes south then that won’t lead to disruption of other microservices.

  • Established around business capabilities - It is not organized around software layers, meaning there is no need for us to create a web MS, a business MS or a Database MS. Instead, we create MS around business capabilities. So we create a microservice for handling:



c.Authenticating Debit/Credit cards

d.Filtering Products

e.And for many more purposes.

These services can be related to mini-applications with a tiny footprint providing a business functionality.

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Posted 2 months ago