JavaScript Developer Job Descriptions, Average Salary, Interview Questions

What Does a JavaScript Developer Do?

A JavaScript Developer is a specialized web developer that mainly works with JavaScript. They use this programming language to create websites, modify or enhance existing code. JavaScript Developers mainly work to provide users with seamless interactivity and deal with website responsiveness. They may use their coding skills to craft website buttons, dropdown menus and lists, modifiable fields, and more.

JavaScript developers will first and foremost need to be experienced with coding, have exceptional troubleshooting skills, and be able to work in a self-motivated environment. Many of these developers will work as part of a team, but they should be expected to design alone. Since much of their work will be independent, they need logical and critical thinking skills to manage websites when there is a critical issue or error. JavaScript developers are an integral part of the web development team and the internet as we know it would not exist without them.

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National Average Salary

JavaScript developer salaries vary by experience, industry, organization size, and geography. To explore salary ranges by local market, please visit our sister site

The average U.S. salary for a JavaScript Developer is:


JavaScript Developer Job Descriptions

Crafting the perfect job description may be the key to finding an exceptional JavaScript developer. To help you with your recruiting search, our team has put together some examples from past openings.

Example 1

When businesses are looking for clean and responsive websites, they turn to us. That’s because we approach every project with the same core concept: The job isn’t done until the client is satisfied with the end product. When we’re creating websites that act as the first impression for a client, they’re trusting us to make that experience seamless, professional, and appealing. 

That kind of trust has empowered us to strive for the absolute best when it comes to project quality, and that’s why we want experts on our team to continue that tradition! We’re currently searching for a JS developer to join us. Our team is composed of collaborative high performers and we’re in need of one more to round out the responsibilities as our client list grows. If you think you’ll fit in well with the team at [Your Company Name], we’d love to hear from you!

Typical duties and responsibilities

  • Design, create, test, and modify web applications and services
  • Work closely with team, project management, and clients to coordinate and create features, software, and promote quality assurance
  • Implement user-centric features for various client applications
  • Implement sustainable and reusable front-end applications
  • Coordinate with back-end developers
  • Follow software engineering best practices, CD/CD, source control, quality, etc.

Education and experience

  • Bachelor’s degree in computer science, mathematics, or equivalent field
  • Minimum 5 years experience in JS position

Required skills and qualifications

  • Fluent in JS ES6+, React, state management, SCSS, CSS3, and functional programming
  • Experience implementing design libraries and microservices to support functional and responsive UI
  • Familiarity with RESTful API, Webpack, NPM, and Jest or equivalent framework
  • Familiarity with Agile methodology development cycles, source control, and Jira task management
  • Experience with TypeScript

Preferred qualifications

  • Cloud platform experience
  • Middle-ware experience
  • ReactNative Mobile experience
  • Experience with Docker, Ansible, NodeJS, and Vagrant

Example 2


  • Developing new user-facing features using React.js
  • Building reusable components and front-end libraries for future use
  • Translating designs and wireframes into high quality code
  • Optimizing components for maximum performance across a vast array of web-capable devices and browsers
  • Style the components using Sass styling and contribute to overall style system

Work environment

  • This is a remote position with possible in-office attendance as requested by management

Physical demands

The physical requirements of this position are described as sedentary work. Sedentary work involves:

  • Exerting up to 10 pounds of force occasionally and/or negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects
  • Sitting most of the time
  • Walking and standing are required only occasionally

Required education and experience

  • 4-5 years of Frontend Javascript Developer experience
  • Strong proficiency in JavaScript, including DOM manipulation and the JavaScript object model
  • Thorough understanding of React.js and its core principles (such as State Management)
  • Experience with popular React.js workflows (such as Redux)
  • Familiarity with newer specifications of EcmaScript
  • Experience with data structure libraries (e.g., Immutable.js)
  • Strong interpersonal skills, including an ability to work comfortably with professors, content experts, and business partners
  • Intellectual curiosity across multiple disciplines
  • Experience managing schedules and budgets is highly desirable
  • Familiarity with RESTful APIs and GraphQL
  • Knowledge of modern authorization mechanisms, such as JSON Web Token
  • Familiarity with modern front-end build pipelines and tools
  • Experience with common front-end development tools such as Babel, Webpack, NPM/Yarn, etc.
  • Ability to understand business requirements and translate them into technical requirements
  • Familiarity with code versioning tools like Git

Example 3

As a member of our software development team you will

  • Assist in the development of innovative software that solves REAL business problems
  • Be a fully empowered member of a cross-discipline Agile team tasked with delivering scalable, extendable, and fully testable code
  • Participate in the on-going development and support of existing applications
  • Participate in strategic projects that improve operational efficiency across WWT’s Human Resources organization
  • Work closely with other developers and analysts to ensure development meets requirements and delivers optimal performance to our end users
  • Collaborate with Product Owner and technical partners to scope the opportunities, identify constraints, and help mitigate risks
  • Develop simple to complex programs on supported database technologies and programming platform
  • Testing the end-to-end solution to ensure complete satisfaction of internal and external users

Required skills

  • Bachelors, Masters, or MBA degree preferably in Computer Science or Management Information Systems
  • 3+ years of experience in modern web development (e.g., HTML5, JavaScript, AngularJS)
  • Developing Single Page applications with JavaScript frameworks such as VueJS or AngularJS
  • Passion for Software Development and well-versed in industry trends such as Mobile, Single Page Applications, Responsive Design, and REST based API’s
  • 3+ years of experience developing RESTful APIs and modules utilizing NodeJS
  • Strong SQL, PL/SQL, and relational database experience
  • System design experience with SOA/REST/Microservices would be a plus
  • Developing large-scale, custom distributed software systems in Java or Grails/Groovy
  • Experience testing – from unit to functional to integration
  • Possess a solid understanding of Agile and Scrum principles
  • Self-motivated with the ability to work independently with minimal supervision

Example 4


  • Work in a team environment to design and develop software for the management, manipulation, and display of a wide variety of data
  • Build reusable components and services using the latest Angular framework
  • Design and implement secure, performant code to develop new user-facing features
  • Implement functional and unit tests to maintain the quality of our codebase


  • 3+ years of experience with web technologies such as JavaScript, HTML, CSS, and RESTful web services
  • Ability to master new technology quickly and to work in a constantly-evolving environment
  • Excellent communication skills and the ability to work with a diverse team
  • Excellent problem-solving, verbal and written communication, design, development, and debugging skills
  • Bachelor’s or master’s in computer science, engineering, mathematics, or related field, depending on position level

Recommended qualifications

  • Experience with JavaScript libraries such as Angular, Angular.js, D3, Node.js, Electron. React, Vue, or other frameworks for developing large web and desktop-based software solutions and products
  • Experience with the Angular web application framework, TypeScript, and latest ECMAScript versions
  • CSS compiler knowledge (e.g., Sass, LESS)
  • JavaScript file bundlers such as Webpack and Rollup
  • Experience building and using browser rendered UI components and graphics systems (SVG, Canvas, WebGL)
  • Experience with data visualization libraries such as D3, amCharts, Wijmo, etc.
  • Knowledge of modern web development tools (e.g. Git, GitHub, npm, Gulp, Jenkins)
  • Experience with Esri’s ArcGIS JSAPI

Candidate Certifications to Look For

  • JavaScript Developer Certificate – This certification from W3Schools is available as a beginner certification for candidates wanting to step into the JS world. Candidates can study the accompanying learning material, books, courses, and webinars to prepare themselves for the exam. Scoring high enough on the exam will also gain candidates an excellency degree notation, further proving their understanding of the language. This is an excellent degree to develop a foundational understanding of JS and should be considered before taking more advanced and complicated exams for other certifications.
  • Certified JavaScript Developer – The International JavaScript Institute, or the IJSI, provides the CJD for candidates who can pass. The program not only assesses the level and understanding of JS, but also offers more advanced concepts to further their competency. The CJD will prove candidates are well-versed in the general principles of programming, JS syntax, expressions, operators, data types, control structures, and more. They’ll also learn about DOM, AJAX, event handling, graphics, APIs, classes, objects, and much more. This is an intermediate-advanced level certification.
  • Microsoft Technology Associate Exam 98-382 – The MTA certification teaches much more than just Java alone, but is well worth it for candidates stepping into the programming world. They’ll learn Windows OS fundamentals, software development, security, Python, HTML, CSS, Java, and much more. For each exam passed, they’ll gain certification in that particular area.
  • CIW JavaScript Specialist – The Certified Internet Web Professional has been one of the top certifications in the United States since the ’90s. This certification specializes in user interactivity and ensures the candidate can entirely handle the front-end work of a web page. This certification teaches intermediate skills like manipulating JS DOM, deploying language objects, program flows, form validation, and creating and using expressions. If candidates are interested in designing websites, UI, or becoming full-stack developers, it’s a great idea to work towards this certification.

Sample Interview Questions

  • How do you create an object in JavaScript?
  • How do you create an array?
  • What’s a name function?
  • Can you assign an anonymous function to a variable?
  • What’s the purpose of the “this” operator?
  • What’s a callback?
  • Can you explain closure? Can you provide an example?
  • What are some of the variable naming conventions?
  • How would you make a cookie?
  • How would you read a cookie?
  • How would you delete a cookie?
  • What are some ways to define a variable?
  • What’s a typed language?
  • What’s the difference between undefined and null?
  • What are some frameworks for JavaScript?
  • Can you explain event bubbling?
  • What’s NaN?
  • What are exports and imports?

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