The front-end ecosystem is constantly evolving and changing. There are changes on the daily basis. Some tools become “bestsellers” in terms of web app development, revolutionizing the workflow, while others become a dead end. So, correcting tools is a big task.
In this competition React js is one tool that has won much heart. React js can be easily labeled as a bestseller. Launched back in 2013, this JavaScript library has quickly won popular affections. Today it is maintained by Facebook, together with the developer community. The leading companies, like Apple, PayPal, and Netflix, use it, while over 32 thousand websites are built using React JS framework.
There are so many benefits of using react js
Here are a few

1.Speed, Flexibility, & Performance
React allows developers to utilize individual parts of their application on both client and server-side, which ultimately boosts the speed.
React code is easier to maintain and is flexible due to its modular structure. This flexibility, in turn, saves a huge amount of time and cost to businesses.
React JS was designed to provide high performance

2.It is SEO friendly

Nowadays SEO has the main part in the growth of the business.
According to Moz, the lower the page load time and the faster the rendering speed, the higher an app will rank on Google.
React has a Fast rendering process which helps to reduce the page load time. Which directly helps to improve the rank.

3.Easy to learn
React is much easier to learn compared to other popular frontend frameworks like Angular & Vue.
It also one of the reasons for getting popular and used by so many Reactjs Development company

4.It helps to create a great user interface
Today, the quality of the user interface in an application plays an important role. If the user interface is poorly designed, then it lowers the chances of an application succeeding.
But, if an application has high-quality UI, then there are better chances that your users will love to use the app.
Therefore, building rich user interfaces is sort of necessary for an application to survive and thrive.
The good news is, react js allows building such high-quality, rich user interfaces through its declarative components, which brings us to our next point.

5.It is used by both Fortune 500 companies and innovative start-ups

Thousands of companies worldwide have chosen React js for their apps, sites, and internal projects.
Still, doubt about what is React js good for? – Check out some inspiring samples of hot solutions: companies built mobile apps with React Native: Airbnb, Walmart Labs, Tesla, Tencent QQ (with more than 829 million active accounts), Baidu Mobile (with more than 600 million users), Bloomberg, list, Gyroscope, Delivery.com, JD.com, GoDaddy and many others.
Sites using React: BBC, Netflix, Dropbox, Coursera, IMDb, PayPal, Dailymotion, Chrysler, American Express, Intuit, Khan Academy, Lyft, Atlassian, New York Times, Reddit, and dozens of others. One of our recent projects, Mochi – Pet Supplies & Food, is also built using React Native, and currently, it gains traction.

Conclusion:
Considering React's pros and cons, it can be easily summed up in three words: non-risky, responsive, and advanced.
This is a reason that there is so many React Js Development company are Growing.