Hire Front-End developer

How to know that the front end developer is the right fit?
A successful software application provides an engaging and interactive experience to users. The key to achieving the highest potential of these applications lies in the hands of good front-end developers. Front-end developers are the brains behind constructing parts of apps that users perceive and interact with. Creating all the customer-facing features is not an easy task. This task will require a talented developer with an undeniable length of experience, who possesses the perfect blend of coding, testing and, integration skills, along with an eye for graphic and UI design. Such a combination will result in an application that users will pine for and competitors will vie for.

The question is, how can you find a front-end developer that possesses the skills, has the right attitude and is the best fit for your projects? Let us break down everything you need to consider during the selection process.

What does a front-end developer do?

Front-end developers create designs for mobile and web applications using top-notch technical coding skills and UI/UX design.
Front-end developers create designs for mobile and web applications using top-notch technical coding skills and UI/UX design. They need to master three core skills: HTML, CSS, and Javascript. JavaScript is a versatile and complex system that allows interactive animation of UI elements. It specializes in front-end development which sets it apart from HTML and CSS. Mastering these core skills in front-end development will contribute to creating the best if not perfect user experience for your business applications.

How can you evaluate a good front-end developer?

A good front-end developer will not only be critical on the app functionality but also the UI and UX. He will also be able to improve the quality of the application by fixing bugs, running manual and automated tests as well as testing the back-end integrations to make sure that those are properly carrying out the front-end functionality.

The ideal hire for a front-end developer should have extensive skills in coding and specializes in UI/UX design. This person should be able to take care of your small projects through all the stages until they are released.

How can you tell if a candidate is the right person for you?

During a critical selection process, one can already tell if a candidate is skillful, driven, and has the right attitude and commitment to a project. But that does not guarantee that the candidate will be the right match. Finding the right candidate also depends on how much in detail you are able to define the project scope.

The details and the complexity of the project with help determine if the candidate has the accurate skill sets that will suit your needs. Top-notch talent is a gem that only good interviewers can source. You can learn How to find Top-notch Talents through DevsData’s guide.

Asking the right questions is another crucial factor in finding out if the candidate is the right fit. He should be able to understand complex technical terms, have the ability to share and describe his ideas in a comprehensive manner, have significant skills and experiences, but most of all he should share the same vision and goals with you.
The ideal hire for a front-end developer should have extensive skills in coding and specializes in UI/UX design

What are the questions to ask in a front-end interview?

Here are examples of front-end questions that will surprise your candidates and weed out the weak ones (needless to say – we often ask them for our internal interviews at DevsData):

Q1. Please describe all the methods for converting a string into an integer in JavaScript?

  • Number function
    var x = Number(“1234”)
  • parseInt
    var x = parseInt(“1234”);
  • parseFloat (Converting number with decimal points)
    var x = parseFloat(“1234.56”);
  • Math.floor
    var x = Math(“1234.45”);
  • Math.round
    var x = Math.round(“1000”)

Q2. What API documentation tool would you require from a Backend engineer when working on a project, why?


  • It is comprehensible for developers and non-developers.
  • It is easily adjustable, it can be successfully used for API testing and bug fixing.
  • The same documentation can be used for accelerating various API-dependent processes.
  • Provides a set of great tools for designing APIs and improving the work with web services: Swagger Editor, Swagger Codegen, Swagger UI, Swagger Inspector


  • Extremely easy deployment
  • Server-Side Rendering ready
  • The widest OpenAPI v2.0 features support
  • OpenAPI 3.0 support
  • Neat interactive documentation for nested objects
  • Code samples support
  • Responsive three-panel design with menu/scrolling synchronization
  • Integrate API Introduction into the side menu
  • redoc-cli with ability to bundle your docs into zero-dependency HTML file

Q3. Have you heard about portals in React? What do they do?

A portal is a way to render an element outside of its component hierarchy, in a separate component.

When that event is rendered, events happening on it are managed by the React components hierarchy rather than by the hierarchy set by the DOM position of the element. Hence the name “portal”: an element sits somewhere in the DOM tree that’s outside of the normal React components tree, but the React component tree that includes it is still in charge. React offers an easy API to do this, ReactDOM.createPortal(), which accepts 2 arguments. The first is the element to render, the second is the DOM element where to render it. A classic use case for this is modal windows.

Q4. What are the “error boundaries” in React and why is it used?

Error boundaries are React components that catch JavaScript errors anywhere in their child component tree, log those errors, and display a fallback UI instead of the component tree that crashed. Error boundaries catch errors during rendering, in lifecycle methods, and in constructors of the whole tree below them.

The reason for using them is that before React 16, JavaScript errors inside components used to corrupt React’s internal state and cause it to emit cryptic errors on the next renders. These errors were always caused by an earlier error in the application code, but React did not provide a way to handle them gracefully in components, and could not recover from them.

Q5. What are the differences between Redux and Mobx?

Mobx is a testing library used to make scalable and simple state management with the help of TFRP (Transparent Functional Reactive Programming). It will help to make the state consistent. It follows the concept that everything that can be derived from the application state, will be derived automatically. Redux is a javascript library for maintaining the application state management. Redux helps to develop the applications that behave consistently in all the environments and helps developers to develop, test and debug the code easily.

Q6. What are filters in Vuejs?

Filters help with applying common text formatting. It is used in two places, mustache interpolations, and v-bind expressions. It mainly filters the data on the DOM level. So you get data that is still intact in the storage but is represented in the custom specified manner. It enhances the presentation of the view layer. The filters are also reusable. You can declare a filter globally and use it on any desirable component. It gives you the power to format your data at the view level.

Q7. Can you explain the difference between coding a web site to be responsive versus using a mobile-first strategy?

Many people mistakenly think they are one and the same when they are entirely different. Coding a responsive website means that you start projecting to the desktop maximum resolution, and then scales down to the smallest screen. A mobile-first strategy is like designing a mobile app and adapting it neatly on tablets and desktop devices without too many modifications. Your layout is based on providing excellent mobile user experience.

Q8. What are components props?

Every instance of a component has its own isolated scope. This means that you can’t directly reference parent data in a child component template. Data should be passed to child components using props. There are custom attributes you can register on a component. When a value is passed to prop attribute, it becomes a property on that component instance.

Q9. What are pseudo-elements in CSS?

There is a keyword added to the selector. By pseudo-elements you can create or define elements that are not on the DOM. They allow styling one specific part of an element. They have no element type as far as the document language is concerned because they simply don’t exist in the DO and can only be created using CSS. For example, it can be used to style the first letter or line of the element. Another function is inserting content before or after the content of the specified element.
Top-notch talent is a gem that only good interviewers can source.


An awesome front-end developer will not only have the right skills, attitude and commitment but he will also make sure to acquire the necessary knowledge in the field to successfully deliver the project. Passionate candidates exude confidence in what they do. They are focused, goal-oriented and quick on their feet. Having such front-end developers on your team is an asset. They will help bring in more clients and ensure your company’s success in the industry.

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Unbeatable tech experience

“I interviewed about a dozen different firms. DevsData LLC is truly exceptional – their backend developers are some of the best I’ve ever worked with. I’ve worked with a lot of very well-qualified developers, locally in San Francisco, and remotely, so that is not a compliment I offer lightly. Their depth of knowledge and their ability to get things done quickly.
Nicholas Johnson