Full Stack Developer Interview Questions

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Full Stack Development is one of the most popular domains in computer science where complete web applications inclusive of front-end, back-end, and databases are developed. Currently, there are over 45,000 job offers worldwide, offering Full Stack Developers positions are becoming more and more popular. The professionals in this field earn an average of ₹12,00,000 per annum. Thus, the field is projected to exhibit a 20% CAGR year-on-year in the foreseeable future as the digital transformation acquires pace.

This blog post is divided into three sections covering all the concepts of Full Stack Development interview questions that you are expected to face while sitting in the hot seat.

1. Basic Full Stack Developer Interview Questions

2. Intermediate Full Stack Developer Interview Questions 

3. Advanced Full Stack Developer Interview Questions

Table of content

• Mention all the ways by which we can include the CSS code in an HTML code
• Explain in brief, what is meant by the term Semantic Elements in HTML
• Describe tags, attributes, and elements in HTML
• What is JavaScript? Explain any four libraries used in JavaScript
• State the definition of the Callback function in JavaScript, and also give the code snippet as an example
• Expand the term MEAN stack and MERN stack, and mention their alternatives
• What is meant by scope in Angular Js? Also, define the different types
• Briefly explain Directives in Angular Js
• What are the features of Node Js? Also, mention why it’s a single-threaded framework
• Define and expand the term NPM. Why do we use NPM with Node.Js

Basic Full Stack Developer Interview Questions for Freshers

Firstly let’s discuss some entry-level questions that you can expect during an interview, these questions are pretty easy and can be answered if you have even basic knowledge of the topics.

1. Mention all the ways by which we can include the CSS code in an HTML code.

• Cascading Style Sheets – CSS, or Cascading Style Sheets, is a language used to style an HTML document. It specifies how an HTML element will appear on a web page.
• Hyper Text Markup Language – HTML refers to a markup language which is used to construct the basic structure of a web page.
• Ways to include CSS code in an HTML document –
  • Inline Method – In this method, the CSS code is included using the style keyword as an attribute in HTML tags.
    Example <p style = “font-size: 10;”> Intellipaat </p> -Intellipaat
  • Internal Method – We have to use tag intag that is the head section of the HTML document.

• • • External Method – We use tag to include a CSS file in the HTML document.

2. Explain in brief, what is meant by the term Semantic Elements in HTML.

Semantics Elements – Semantic Elements in an HTML document are the elements which clearly describe themselves to both the browser and the developer. Semantic elements make HTML more understandable by defining different sections and layouts of the web page in a more readable manner.

3. Describe tags, attributes, and elements in HTML.

Tags in HTML – In HTML, tags refer to keywords that are enclosed inside angular brackets and are used to display the HTML elements.

Attributes in HTML – Attributes are the entities which are used to show the features and additional properties of an HTML element.

HTML Elements – HTML elements are a collection of HTML attributes and HTML tags that are used to display the content of an HTML page on the user’s screen.

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4. What is JavaScript? Explain any four libraries used in JavaScript.

• JavaScript –
  • JavaScript is a typescript-based, general-purpose programming language that works on the principles of object-oriented programming.
  • JavaScript happens to be a very popular programming language which is used for both server-side and client-side scripting.
  • There are three ways by which we can include JavaScript in our HTML document-
    • Embedded Coding- In this method we use the <script> tag in the HTML document to include JavaScript code.
    • Internal Linking – In this we use HTML event attributes.

Example - <a href="#" onClick="alert('Intellipaat's Website is Ready !');">Okay!</a>

• • • External Linking – Here we use <script> tag with an attribute src.

Syntax - <script src="intellipaat.js">

• Four Libraries used in JavaScript –

JavaScript is a revolutionary programming language which has transformed the way how world wide web used to work. Libraries in JS cover all the domains of development.

For example, Vue.Js, React Js, Angular.Js, Next.Js, Node.Js, Express.Js, and many more.

• React Js – React Js is a type of JavaScript-based open-source framework developed by Meta. The main purpose for the introduction of this premium framework was to build an intuitive UI for web applications.
• Express.js – Express.js, or just Express, is a Node. js-based back-end web application framework for building RESTful APIs that are free and open-source under the MIT License. It is designed for the creation of web applications and APIs.
• Next.Js – Next.Js is an open-source React framework based on JavaScript. The framework extends the functionality of React-based web applications including server-side rendering and the generation of static websites. The framework is developed by Vercel.
• Vue.js – Vue.js is a free and open-source JavaScript model-view-ViewModel front-end framework for creating user interfaces and single-page applications.

5. State the definition of the Callback function in JavaScript, and also give the code snippet as an example.

The callback function in JavaScript is a type of function which passed as arguments to another function. Irrespective of the sequence by which the functions have been defined it is executed based on the function calls. The execution takes place after the execution of the previous function has been completed.

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6. Expand the term MEAN stack and MERN stack, and mention their alternatives.

MEAN stack – MongoDB, Express.Js, Angular.Js, Node.Js

MERN stack – MongoDB, Express.Js, React.Js, Node.Js

Stacks are prepared based on compatibility between different technologies. A few of the efficient stacks are –

• MEVN – MongoDB, Express.Js, Vue.Js, Node.Js. MEVN is used to develop full-stack applications efficiently and effectively. It is a to-go alternative for MERN and MEAN.
• LAMP – Linux, Apache, MySQL, PHP. It is one of the most popular cloud-based application development stacks.
• PERN – PostgreSQL, Express.Js, React.Js, Node.Js. PERN is used to develop applications based on CRUD operations.

7. What is meant by scope in Angular Js? Also, define the different types.

In Angular.Js the term “Scope” refers to a binding part between HTML’s view and JavaScript’s controller. Also, it contains the application’s data and objects. There are two types of scope in Angular.Js –

• $scope – A $scope is a JavaScript object used to communicate between the controller and the view. $scope essentially connects a view (DOM element) to the ViewModel and functions provided in a controller.
• $rootScope – The top-most scope in Angular.Js is $rootScope. There can only be one $rootScope in an app, which is shared by all components. As a result, it acts in the same way as a global variable. All other $scopes are children of the $rootScope.

8. Briefly explain Directives in Angular Js.

Directives in Angular are described as classes that can add new functionality to template components or alter current behaviour. Directives in Angular are used to manipulate the DOM, whether by adding new elements to the DOM, deleting ones, or modifying the look of the DOM elements.

There are three types of directives present in Angular.Js –

• Component Directive
• Attribute Directive
• Structural Directive

9. What are the features of Node Js? Also, mention why it’s a single-threaded framework.

Node.Js is a very popular framework, that is used for back-end development. It uses a powerful V8 JavaScript engine which is used to execute JavaScript code outside of the browser. Node.Js facilitates developers a lot in back-end development, various pointers due to which Node.Js is preferred by the developers are –

• Open-Source Framework
• Asynchronous Programming
• Utility of NPM
• High Performance
• High Uptime
• High Scalability
• Single-Threaded Framework

Node.Js is a type of single-threaded framework. The working principle of Node.Js is based upon single-threaded event loop model architecture similar to that of JavaScript which is used to handle multiple client requests.

10. Define and expand the term NPM. Why do we use NPM with Node.Js?

NPM (Node Package Manager) is a type of JavaScript software registry over the web that is used by developers to share, download, and borrow various types of packages that are used for installation and dependencies resolving purposes.

Node Package Manager has three different types of components –

• Website – The website is used for package discovery and profile management.
• Command Line Interface – CLI is a type of terminal used to run NPM in the developer’s system.
• Registry – A registry is a type of database which have JavaScript files and associated metadata.

In Node.Js Node Package Manager is used to set up the Node.Js development environment in the user’s system, download the needed packages, and resolve dependencies issues.

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11. What is CORS? How to include CORS in Express.Js?

CORS (Cross-Origin Resource Sharing) – CORS is a browser mechanism that allows web pages in one domain to have limited access to resources in other domains (cross-domain requests). This enables browser client scripts to interact with and access resources from different origins.

As a result, the SOP is extended and made more flexible (Same-Origin Policy). Same-origin restrictions limit a website’s access to resources outside its source domain. CORS allows access to diverse online resources across several domains. CORS can be used to integrate web scripts when they request a resource with an external origin (protocol, domain, or port) from their own.

To enable cross-origin resource sharing In Express.Js we use CORS NPM modules. First, we have to install CORS in the system, and then we have to enable CORS for Express.Js. If CORS is not configured correctly then the website is vulnerable to CSRF (Cross-Site Request Forgery) attacks.

12. What is meant by the term “Replication” in MongoDB?

Replication in MongoDB happens to be a practice of syncing data across several servers. With numerous copies of data on separate database servers, replication offers redundancy and boosts data availability. Replication safeguards a database against the loss of a single server. Users may also recover from hardware failures and service interruptions through replication. Users can assign one copy of the data to disaster recovery, reporting, or backup.

13. Mention the ways by which we can create a new database in PostgreSQL.

There are two ways by which we can create a new database in PostgreSQL–

• Using pgAdmin – In this method, we use the GUI provided by pgAdmin to create the PostgreSQL database.
• Using SQL Shell – Here, in this method, we use the CLI provided by the SQL. Users have to write commands in the SQL shell for the creation of a new database.

14. What is the difference between the WHERE clause and the HAVING clause?

Difference between WHERE clause and HAVING clause-

15. Define RDBMS. How do RDBMS and DBMS differ from each other?

The acronym RDBMS refers to Relational Database Management System. An RDBMS is a type of DBMS which is used to store data in a tabular form based on rows, it connects similar data components. An RDBMS provides features that ensure data security, correctness, integrity, and consistency. It’s essentially a tool that lets users build, remove, and update relational databases. A relational database is a database system that stores and retrieves data in the form of rows and columns in a tabular format.

Difference between RDBMS and DBMS-

Intermediate Full Stack Developer Interview Questions

Welcome to yet another section of the blog. In the previous section we covered the basics, and I hope it gave you an idea of what the recruiters seek in the basics. In this section of the blog, we will talk about the intermediary level of questions with their answers. These questions seek an in-depth understanding of the concepts present in the technology.

16. In what real-life scenarios should we consider MongoDB for our database?

When your data is document-centric and does not integrate well within the schema of a relational database, when you want to support vast size, when you are rapidly prototyping, and in a few other circumstances, NoSQL databases like MongoDB are an excellent solution.

Possible use cases for MongoDB are as follows –

• Product Data Management System
• Operational Intelligence
• Product Catalogue
• Mainframe Offloading
• Real-Time Data Integration

17. In PostgreSQL, what is meant by Cluster and Non-Cluster Indexes?

Cluster Indexes – It is a type of index used in PostgreSQL that is used to arrange rows of data in a database based on their key values. There can only be one index based on clustering in a table in a PostgreSQL database. These clustered indexes may also be used to decide the order of the data, which is how data is stored in the database. Typically, the primary key in an RDBMS allows you to construct a clustered index based on that single column.

Non-Cluster Indexes – In non-clustered indexing, the data and its associated index is kept separately the concept of pointer works here, there exists a pointer pointing towards the location of data. This type of indexing is also known as secondary indexing. There can exist multiple non-clustered indexes based on the specified table in a PostgreSQL database. Based on the comparison between cluster index and non-cluster indexing, cluster indexing is of a larger size.

18. State the difference between the DROP command and the TRUNCATE command in SQL.

The difference between the DROP command and the TRUNCATE command in SQL are as follows-

19. Explain the concepts of Buffers and Streams in Node.Js.

Buffers – Buffers in Node.Js refers to the pieces of memory allocated on the user’s system used to store raw binary data. Users can only once set the size of the buffer cannot be changed. Buffers can only handle binary data and cannot be resized, and buffer possesses similarities to an array but, arrays are resizable. A byte is represented by each integer in a buffer. To print the Buffer instance, use the console.log() method.

Streams – In Node.Js, the term “Stream” refers to an abstract interface that is used with the working of streaming data during a process. To implement the stream interface, we use an API provided by node:stream. There can exist various stream objects in Node.Js.

Types of stream in Node.Js –

• Readable Stream – It is a type of stream in Node.Js that is used to create a stream of data for reading purposes.
• Writable Stream – Writable stream is used to create a stream of data for writing purposes.
• Duplex Stream – In Node.Js, duplex stream refers to a type of stream that is created to make a stream of data which is capable of reading and writing.
• Transform Stream – It is a type of stream that is used to create a stream of data for both reading and writing purposes but we can change the data during the process of reading and writing.

20. What do you understand by the term Scaffolding in Express.Js? Does MVC support Scaffolding?

The term “Scaffolding” in Express.Js refers to the creation of a  basic skeleton structure for the to-be-developed web application. Scaffolding helps users to create their profiles in the public domain. Also, scaffolding helps in the addition of middleware in the application, the creation of separate route files, and many more. It starts the basic building of the application for us.

21. Differentiate between these technologies; Node.Js and Django.

Below-mentioned is the differentiating pointers based on which Node Js and Django differ from each other-

22. Why do we do interpolation in Angular.Js? Briefly explain the ways by which Angular Js extends HTML.

Interpolation in Angular.Js refers to the way by which we transfer data from any TypeScript code to an HTML view. By using this method we can encapsulate expressions between texts to evaluate the value of the expression. Interpolation in Angular.Js works on one-way data binding. By using this we can bind data to our logic whereas,, we can only use string parameters.

Syntax of Interpolation – {{expression}}

Angular.Js uses directives to bind the HTML data with the Angular.Js application, it extends HTML in three ways –

• ng-app – This directive in Angular.Js is used to define the Angular.Js application that we want to develop.
• np-model – We use this directive to bind the value of HTML controls.
• ng-bind – In Angular.Js, this directive is used to bind the HTML view and the application data.

23. What are State and Prop in React Js? Explain briefly the concept by giving examples.

State in React Js – The term “State” in React Js refers to a type of variable that exists inside a component and is used to store data or information about the component. The state has a similar working principle as that of a local variable it cannot be accessed or modified outside its component. To modify the state we have to use this.setState, when this is applied the state class re-renders itself.

Example of State –

Prop in React Js – In React Js, the term “Prop” is an alias name given to properties where it acts like an object which is used to store attribute values associated with various types of tags. The working principle of props is similar to HTML attributes. Props behave as a read-only component in React Js. Props are immutable.

Example of Prop –

24. What is the difference between var, const and let keywords in JavaScript?

Below-mentioned are the differentiating pointers between var, const, and let variables-

25. What is DOM manipulation? How it is different from BOM? Explain the related information in detail.

DOM Manipulation – DOM (Document Object Model) in JavaScript refers to a hierarchical tree-like structure which is used to show the relationship between various types of HTML elements. The working principle of DOM is very simple; it is a tree of nodes created by the browser. Each node contains distinct attributes and methods that may be modified with JavaScript.

Difference between DOM and BOM –

26. State the different ways by which we can create objects in JavaScript.

There are three different ways by which we can create objects in JavaScript and they are as follows-

• Using object literal.

• By creating an instance of an Object directly.

• By using the constructor function.

27. Comment on Box Model in Cascading Style Sheets.

One of the most basic ideas in Cascading Style Sheets is the CSS Box Model. The Box Model in CSS refers to a type of container which is used to design the layout of a web page from scratch, it consists of various properties like margin, padding, border, and content area. The web browser renders each element as a rectangular box in accordance with the CSS box model.

In CSS, Box-Model has several properties which are stated below-

• Content: This property is used to show text, images, and other elements that can have their sizes adjusted using the width and height properties.
• Padding: This attribute is used to add space inside any defined borders around the element.
• Border: This property is used to define the style, colour, and width of the border as well as to cover the content and any padding.
• Margin: The border region of an element is surrounded by space created by this attribute.

28. What are the various kinds of CSS selectors? Explain.

Selectors in CSS refer to ways which are used to locate a particular HTML element in the CSS file to style. In CSS, there are five types of selectors, they are –

• Simple Selectors – In simple selectors, we select elements based on their id, class, and name.
• Combinator Selectors – In this, elements are selected based on the relationship between them.
• Pseudo-Class Selectors – This selects elements based on their state.
• Pseudo-Elements Selectors – This type of selector selects a part of the HTML elements and styles it.
• Attribute Selectors – Attribute Selectors are used to styling an HTML element based on its attribute or its attribute value.

29. What is a table in an HTML document? Mention all the associated tags to it.

A table in HTML is a collection of rows and columns which is defined using <table> tag. An HTML document consists of various types of tags associated with table tags.

30. Explain different types of media tags in HTML. Also, give their syntax as well.

Various types of media tags in HTML are as follows –

• <audio>: To incorporate sound files into a web page we use <audio> tag, which is a type of inline element.

<audio>

            <source src=”sample.mp3″ type=”audio/mpeg”>

</audio>

• <video>: We use <video> tag to embed videos in our HTML document.

<video src=” ” controls>   </video>

• <source>: In HTML, <source> tag is used to attach multimedia files like audio, video, and pictures to an HTML document.

<source src=” ” type=” “>

   …

</source>

• <embed>: In an HTML document, <embed> tag is used to embed external apps, most of which provide multimedia information like audio or video.

<embed attributes>

• <track>: It is used to provide text files that should be viewable while the video is playing, such as subtitles, caption files, or other text-containing files. As a result, the sectors for the audio and video elements are straightforward.

<track Attribute>

Alright, it was a bit much but guess what, you have gained a lot of knowledge which will help you to crack your dream job. Coming up is an advanced level of knowledge is waiting for you, the amount of knowledge you will gain will leave you in awe!

Advanced Full Stack Developer Interview Questions for Experienced

First of all, I congratulate you on making it to the end, I hope you have cleared all the concepts previously mentioned before. Now welcome to the final section of the blog, so far we have covered thirty questions ranging from easy to medium difficulty. Now, it the time to exceed our limits and go for the real thing.

In this section of the blog, we are going to offer you a huge knowledge dump which will cover the rest of the leftover topics in the field of full-stack web development.

31. What is the concept of routing in Angular.Js? Explain its significance as well.

Routing in Angular.Js refers to the way by which users can switch between various web pages while using a single-page web application. This technique allows the users to develop different types of URLs that can be used to navigate through different components of the web application.

To do this ngRoute module is used by the developers to access various components of the web page without reloading the whole application, this must be done after adding the ngRoute module to the dependencies.

Because of the concept of routing in Angular.Js, the developers can prepare a single-page web application that can redirect to different web pages.

32. What is the difference between ng-show and ng-if directives in Angular.Js?

It has been seen that both terminologies show similar behaviour. These terms usually govern the performance of the web application developed using Angular.Js Check out the difference between them to have a better understanding of them-

33. What does the term React Hooks refer?

The concept was first introduced in React version 16.8. After the introduction, the developers were able to perform functional programming. The term “React Hooks” refers to a type of function based on JavaScript which is used to isolate the functional component of a reusable function.

By using React, Hooks developers can use various react features without writing the classes which means we cannot write “use react hooks” in class components.

34. What are the benefits of utilising React Js for front-end development? What is HOC in React Js?

There are numerous reasons to prefer React Js over any other front-end development framework for the following reasons-

• React Js offers better functionality and faster rendering of web pages.
• It is a type of very flexible and stable framework, it also offers better testing and smooth development.
• Components of React Js are highly usable and mainly focus on UI designs.
• React Js is trusted by many tech giants and also it possesses very rich community support.
• React Js is a very secure framework as it provides a unique data abstraction layer which prevents unnecessary code exposures to the users.

HOC in React Js refers to Higher-Order Components which is a type of advanced method used by the developers for reusing the logic of a component’s functionality. It takes the previously developed original component and after processing it returns the enhanced results.

35. How can we use clustering to enhance the performance of Node.Js?

Clustering is an important concept in Node.Js, it enhances the performance of the Node.Js application, because Node.js apps operate on a single processor, they cannot make use of a multi-core machine by default. Cluster mode is used to launch numerous node.js processes, resulting in many event loop instances. When we use the cluster in a Node.Js app, many node.js processes are launched in the background, but there is also a parent process called the cluster manager that is in charge of monitoring the health of the individual instances of our application.

36. What is Stub?

Stubs in Node.Js refer to a type of small program regime which acts as dummy objects and can be used as substitutes for larger programs at the time of testing. These small programs affect the functionality and behavior of the various components and modules.

37. Define Middleware. Mention all the types of Middleware in Express.Js

Middleware is a type handler in Express.Js which is used to access the request-response cycle of the application. It acts as a function which holds the objects of request and response. After the server receives the request and before the controller actions transmit the response, middleware is invoked.

Various types of middleware in Express.Js are stated as –

• Application Level Middleware
• Router Level Middleware
• Error Handling Middleware
• Built-inMiddleware
• Third-Party Middleware

38. What are Shards in MongoDB? Comment.

A shard is a type of single instance in MongoDB which is used to hold the subset of sharded data. It can be brought into action as replica sets to provide data redundancy and increase the availability of the data. In MongoDB, a complete set is a combination of multiple shards. The process of distributing this type of data over multiple host locations is known as sharding. The concept of sharding in MongoDB is achieved by splitting up data into smaller modular instances.

39. Explain in detail about DDL, DML, DCL, and TCL commands in SQL.

Data Definition Language (DDL): It describes the data structure, which includes commands such as CREATE, ALTER, DROP, and so on.

Data Manipulation Language (DML): It is used to alter the database’s existing data. SELECT, UPDATE, INSERT, and other commands fall within this group.

Data Control Language (DCL): It governs access to the database’s data. GRANT and REVOKE are examples of commands in this category.

Transaction Control Language (TCL): This language is used to manage database transactions. COMMIT, ROLLBACK, SET TRANSACTION, SAVEPOINT, and other commands fall within this group.

40. Name various datatypes present in PostgreSQL.

Various types of datatypes in PostgreSQL are as follows –

• Numeric types
• Character types
• Temporal types
• Boolean
• UUID
• Geometric primitives
• Arbitrary precision numeric
• XML
• Arrays etc.

41. What is meant by a CSS Preprocessor? What are the terms Sass, Less, and Stylus mean? Why do people use them?

CSS Preprocessor – A CSS Preprocessor is a tool that uses its programming language to extend the fundamental capabilities of vanilla CSS. It enables us to employ complicated logical constructs like variables, functions, mixins, code layering, and inheritance, to mention a few.

SASS – SASS (Syntactically Awesome Style Sheets) is one of the CSS preprocessors which extends the functionality of CSS. It reduces the repetition of CSS statements.

LESS – LESS (Leaner Stylesheets) is a CSS language extension that is backwards compatible. It enables us to use features such as variables, nesting, mixins, and so on in a CSS-compliant syntax. SASS has affected LESS, which has influenced SASS’s newer “SCSS” syntax.

Stylus: Stylus offers a high level of syntactic freedom, supports native CSS, and allows the elimination of brackets, colons, and semicolons. It does not define variables with @ or $.

42. State the difference between Adaptive and Responsive designs.

Here are the differences between Adaptive designs and Responsive design

43. Comment on the boilerplate of an HTML document.

When developing a new website, it is essential to have a solid foundational coding structure. A boilerplate code or simply a boilerplate is required for this foundation. In basic terms, they are parts of code that are repeated in several locations with minimal to no variation. A boilerplate in HTML is a template that you will include at the beginning of your project. This boilerplate should be included in all of your HTML pages.

44. What is in HTML? Why do we use it? What are the differences that HTML-5 have with previous versions?

in an HTML document refers to a type of declaration for the browser, which tells the browser that the present document is an HTML or XHTML document. Moreover, it also specifies the version of the HTML document in which the page is being written. is neither a tag nor an element, also it’s not case-sensitive and does not require a closing tag.

Syntax of is as follows –

45. Is there any difference between Client-Side and Server-Side? If yes, then mention the differentiating pointers.