Top 30 Full Stack Developer Interview Questions And Answers
Full-stack development generally refers to the end-to-end software development of both the layers such as the front-end and the back-end side of any application. The whole web development process involves primarily three different layers such as the presentation layer (the front-end layer that directly deals with the user interface and interactivity), the second layer is business logic (the back-end part that deals with data manipulation), and the most important database layer. Full-stack development takes care of all the software development steps starting from the conception of an idea up to the actual final product.
What is Full-stack development?
A full-stack development, for example, is a process that is a composition of all the components required for the front-end and the back-end of the application development. The full-stack process has a lot of work to do with multiple layers at the same time such as front-end, back-end, database, and DevOps activities, and combining them will have one product used by the customers.
Having a specialized developer work on each of the different sub-systems of the web application development process proves quite complex to be developed and expensive at the same time. Many tech companies are hiring actively for the role of full-stack developers who are proficient in working across multiple stacks whenever required.
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What is the salary of a Full stack developer?
The demand for the full stack developer has been increasing and to cater to the demands of the market, companies are making a huge offer to the developers, and as per the report of Payscale, the avg salary of the full stack developer in the USA is 75K$ which is an attractive and a huge number.
Whereas in India, the average salary in India of the full stack developer is INR 6.5 LPA Full stack developer salary in India again depends on multiple factors such as the choice of technical stack, location, company size, global exposure, and many more. It has exceptionally high job satisfaction, so many Full Stack Developers stay on to eventually reach six figures the compensation. There are also freelance Full Stack Developers who have a little bit of freedom with their pay in that way. Explain the Roles and the Responsibilities of the full stack developer
By now, we all are familiar with the brief about a full stack developer is one who manages the comprehensive product development that includes the duties of the front end, back end, and all other responsibilities such as code versioning, communication skills, etc. Below are some of the roles that a full-stack developer may perform during his tenure in the organization or as an independent consultant.
Work with the group of development teams and the product managers to define the robust software solutions
Write effective APIs using the various back end framework and languages
Build the front end of applications through the user-centric design approach and visual experience
Design client-side and server-side architecture for getting better accessibility and scalabilities
Test the newly designed software to ensure the highest level of responsiveness and the efficiency
Develop and manage database systems and applications
Troubleshoot, debug and upgrade the existing software
Apply a robust security environment and the user data protection settings
Continuously working with data scientists and business analysts to improve software periodically through the feedback
Build features and applications with a mobile responsive design that works across the group of devices and resolutions
Attending scrum or related meetings for the task measurements across the teams
What is the role of the Front-end in full-stack development?
Front-end development, as mentioned, mostly has to do with the management of what people interact with and see in a software application. Having web pages or mobile applications that are easily navigable and efficiently interactive is integral for users to continue to utilize your software.
Those who work on the front end have knowledge of client software like HTML, CSS, and JavaScript. Additionally, there are tons of frameworks and libraries are there to cater the front-end development such as React, Angular, and Vuejs that uses HTML, CSS, and JavaScript to create the crafted solution for the front-end of the application.
What is the role of the Back-end in full-stack development?
Backend application development is also known as server-side programming or development. It is the thing that the users don’t see directly or interact with and contains the activities which are happening at the back of the door that occurs when the user performs any type of action on a particular website or webpage. It primarily focuses on a few things such as database management, backend business logic building, API implementation, and servers.
The backend side of an application is a combination of the specific servers, backend-centric applications, and single or the collection databases at a time. The codebase created by the backend developers/engineers helps the frontend layer of the application for communicating with the databases and storing data into the database accordingly, reading data from the database periodically, updating the existing data, and deleting unused data or information from the database completely.
For example, the content and layout for a form would be created on the client-side, but when the users submit their information it further gets processed on the server side and the data can be stored in the database.
What are the current full-stack technologies available?
Whether it is mobile application development or web application development, tech enthusiast companies or an individual needs emerging technology to elevate their business to the next level. That is the reason that they hire either a specialized front-end developer or a back-end developer, and that completely depends on the technology needs. But these days, people have realized that instead of hiring specialized front-end developers and separate back-end developers, it is highly beneficial to hire full-stack developers for their full-stack development projects.
As per the current full-stack technical stack, there are three different variations available.
MERN Stack
MEAN Stack
LAMP Stack
What is DevOps?
DevOps which denotes “Development Operations” is the combination of the best practices and a wide variety of tools designed specifically to increase an organization’s technical ability to deliver software applications and services which is faster than traditional software development processes. This speed enables every organization to serve better to their enterprise customers and compete more effectively in the emerging tech market.
In simplest terms, DevOps is all about removing the hurdles between traditionally soiled teams, development, and operations. Under the DevOps model, the development and operations teams work closely across the entire software application development lifecycle, starting from the core development and testing through the deployment to operations.
What are various DevOps Tools?
CI/CD pipeline engines
CI/CD allows the DevOps teams to frequently validate and deliver robust applications to the end-users through automation during the development lifecycle.
Monitoring
The DevOps monitoring tools enable the DevOps developer to observe the application performance and security layer of the code releases of the systems, networks, and the complete infrastructure.
Containers
Containers are the runtime platform for the software on a shared O/S. Docker is the most well-known containerization software, while Microsoft also offers specific windows based container options.
Artifact repositories
Source code is compiled into an artifact for testing. Artifact repositories enable version-controlled, object-based outputs effectively.
Configuration management
Configuration management systems enable IT, executives, to provision and configure the software, middleware, and the infrastructure based on a script or the templates.
Code repositories
Source code repositories enable multiple developers to work on the same set of source code. The developers check code out and are based upon the changes, and they can revert to a previous version of code whenever needed. The version control tools keep a record of all the modifications made to the source code repository. Without using the code repository, developers may struggle to get which changes are made recently and which versions of the code are available for the end-users.
How many DBMS technologies are available for full-stack development?
As a full-stack developer, it is very important to know how to work with databases and DBMS systems. A database in a web application is a place where we store the user data and organize our project's data. There are so many DBMS platforms and technologies available to work with.
SQL
PlSql
MongoDB
PostgreSQL
MS SQL Server
IBM DB 2
ElasticSearch
Redis
Database management (DBMS) is also an essential part of full-stack development. They must be able to work with the basic database functionalities such as storing, retrieving, creation, management, manipulation, and deletion of data. Knowledge of database software like Oracle, MySQL, NoSQL, and PostgreSQL is one of the core skills of a full-stack developer.
What is the use of CI/CD in full-stack app development?
The concept of the CI/CD refers to the software development and its deployment best practices for DevOps under the agile methodology or other such methodologies.
CI/CD automates the complete deployment cycle starting from the source code management, quality assurance, and code quality up to the final deployment, thus, it enables the software development teams to focus on meeting the desired business goals, code quality, and security. It is CI/CD that effectively empowers the DevOps environment in many of the principles of collaboration and automation.
Explain the use of Git in application development
Git is a code version control system that is being used for keeping the track of all the changes of files in the existing project. By using Git, it lets you always have a track record of all the adjustments and return to the specific versions whenever needed. Using Git is always easy to learn and takes up minimal space and configuration with high productivity.
One of the primary features that make Git extremely simple to use is the ability to merge changes from several people into a single source. We can always use GitHub or some other online hosts where we can also store backups of your files and their revision history.
Some of the advantages of using GitHub is like completely open sources, higher development productivity, ease of configuration, and it is accepted by all the tech giants in the world.
How Responsive design can be helpful in app development?
Responsive web design websites are the type of websites that are compatible for adapting to all screen sizes and resolutions, not just only for desktops but also for other device types such as mobile, tablets, and sometimes even huge devices like television.
Responsive web design is a web design strategy that automatically renders the website according to the various screen size or the viewport size. Thus, the website looks and feel (i.e. design, layout, and the user experience (UX)) should remain uniform, irrespective of the device being used for accessing the website.
Having a responsive website attracts the customer as they are accessing the designs/website from multiple devices and most mobile devices, so having responsiveness with the application adds an advantage to cater large audience.
What is the Architecture design pattern available for full-stack app development?
There are so many different programming languages, architectures, and other concerns in the world and that can be difficult to figure out where to start the software development. That's where the design patterns come in and play an important role.
A design pattern is something like a template or architecture pattern for your projects. It uses certain conventions and you can expect a specific kind of behavior out of it for a specific purpose. These patterns were made up of many developers’ experiences so they are really like different sets of best practices.
There are a total of 23 official patterns from the book Design Patterns - Elements of Reusable Object-oriented software which is considered one of the most influential books on object-oriented theory and software development. We are going to cover a few of the design patterns below.
Singleton Design Pattern: The singleton pattern only allows a class or object to have a single instance and it uses a global variable to store that instance
Decorator Design Pattern: It adds responsibilities to an object dynamically
Observer Design Pattern: This pattern intimates the group of objects when any the change occurs
Strategy Design Pattern: This pattern encapsulates the different algorithms using a separate object which can be chosen at run-time
What is Docker?
Docker is a popular open-source containerization platform and it enables developers to package the applications into the container that is the standardized executable components that combine application source code with the operating system (O/S) libraries and dependencies that are required to run that code in any of the environments.
Containers generally simplify the delivery of distributed applications and have become quite popular as all tech organizations shift to cloud-native development and hybrid multi-cloud environments.
One of the primary benefits of using the Docker is its portability and versatility that it makes your applications run in any environment. We can use it anywhere because the Docker makes them convenient to pack and ship accordingly.
What is the use of REST and Soap API?
SOAP is a type of protocol that was designed before the existence of REST and came into the picture. The main propaganda behind the design of the SOAP API was to ensure that the programs built on different platforms and programming languages can easily exchange the data.
The REST API was designed specifically for working with components such as files, media components, or other types such as objects on a particular hardware device. Any web service that is defined on the principles of REST API can be called a Restful web-services. Restful web service would use the normal HTTP verbs such as GET, POST, PUT and DELETE for working with the required components.
What is CORS?
The Cross-Origin Resource Sharing (CORS) is a browser mechanism that allocates access to the resources which is located outside of given domain permissions. It extends and adds flexibility to the same-origin policy (SOP). However, it also provides the potential for cross-domain attacks, if a website's CORS policy is poorly configured and implemented. Keep in mind that the CORS is not a protection against cross-origin attacks such as cross-site request forgery (CSRF).
It is quite recommended to enable Cross-Origin Resource Sharing (CORS) as it allows for additional freedom and functionality for websites.
What is MEAN stack?
The MEAN word is a collection of four different JavaScript technology which is MongoDB, Express, Angular, and NodeJS.
The MEAN stack is a software stack that is a set of the technology layers that make up a modern tech application, that’s built entirely in JavaScript. The MEAN stack represents the key feature of JavaScript as a candidate for full-stack development language, which is running everything in an application starting from the front-end and up to the back-end. Each of the initials in MEAN stands for a specific component in the stack:
What is the MERN stack?
The MERN (MongoDB, Express, and React & NodeJs) stack is a popular collection of the various technologies that enable faster application development while having a modular development approach.
It is quite popular as it is used by developers worldwide. The main agenda of using the MERN stack is to develop the applications using JavaScript language only. This is because the four technologies that make up the technology stack are all JS-based. Thus, if anyone has the knowledge and they know JavaScript, then the back-end, front-end, and database can be operated easily using the specialized full-stack developer.
What is the LAMP stack?
The LAMP stack is one of the popular open-source solution technical stacks that is used primarily in web development. The LAMP stack consists of four different components which are necessary to build a fully functional web application development. The first letters of the names of the components make up the LAMP acronym as given below.
L = Linux which is an operating system used to run the set of the components of the application
A = The Apache HTTP server is a web server software that is used to serve static web pages effectively
M = The MySQL is a popular and powerful Relational Database Management System (RDBMS) used for creating and managing web databases for the application
P = PHP, Python, and Perl are the programming languages that can be used to create web applications.
Each component given above represents an essential part of the LAMP stack. And together, the components are used to create database-driven & dynamic websites effectively.
What is the use of the NPM package manager?
The Node Package Manager (NPM) is a popular JavaScript package manager most notably used in conjunction with Node.js, although it can be used independently as well where we have an NPM directory from which we can select any NPM package and configure it in our application. It gives us all the control over our project’s internal dependencies and provides an effective way to contribute to the open-source community.
We can get started by simply running the command npm install package_name and can inject any useful NPM dependency into your application wherever needed.
What Is Object-Oriented Programming (OOPs)?
Object-oriented programming (OOPs) is a fundamental programming pattern used by almost all developers at some point of time in their development career. The OOP is the most popular programming paradigm and it should be taught to the newbie developers as it is a standard way to do the software/application development for most of a programmer’s educational career.
Below is the building block of the OOP.
Classes
The class is a data structure that contains the various data members, member methods, properties, constructor, destructor, indexers, and nested types which creates a collection of all the data members.
Methods
The methods encapsulate the functions that handle the data and the behavior of an object instance.
Attributes
The Attributes refer to the characteristics of the object i.e. variables.
Objects
The object in OOP represents the class and is primarily responsible for the memory allocation of its data members and member functions. An object is a real-world entity having attributes and behaviors.
What is the 3-Tier architecture pattern?
The 3-tier architecture pattern is a client-side & server-side architecture pattern where the functional business logic, complete data access, the data storage of the application, and user interfaces are developed and maintained as independent modules on separate layers that work independently as well while having interconnectivity.
Every 3-tier architecture consists of three layers as given below.
Presentation layer
Application layer
Data layer
The presentation layer is responsible for showing the user interface to the end-user, the application layer process the user data, and the data layer allows us to store the user data for future use.
What are Microservices?
Microservice architecture, or simply microservices, is an effective method of developing software systems/applications that purely focuses on building single-function modules with well-defined interfaces and operations logic. The tech trend of micro-services has grown popular in recent times as all the enterprises are looking to become more agile and move towards a DevOps and continuous testing environment/space.
A microservices framework creates an extensive scalable and distributed system that avoids the bottlenecks of a central database and application that improves the overall business capabilities, such as adapting the continuous delivery/deployment (CI/CD) applications and modernizing the technology stack.
What is a Web Server? And what are various web servers to host?
A program that uses the HTTP protocol for serving the files or the directory that creates the web pages for end-users in response to their requests that are sent by the HTTP clients of their computer is called a web server.
A web server is never disconnected from internet connectivity. Every web server has a unique address that comprises a series of four numbers between 0 and 255 for identifying each web server uniquely. These numbers are separated with a period (.) sign.
Below are some of the popular web services where we can host our stuff.
Microsoft IIS web server
Apache web server
Apache Tomcat
Nginx web server
Lighttpd
Caddy
Jetty
Explain the use of error handling in web development
Error handling concepts may be imagined while writing the scripts or the programs that work when everything goes as expected is a good sign for the software. But making your programs/scripts behave properly when encountering unexpected conditions is where the task gets challenging.
Most of the software errors that an application encounters can be primarily grouped into a few categories which are explained below.
Input Errors:Information provided by the user is unacceptable for some reason such as not-matching input format, less number of characters for the input, unknown format, etc. It includes errors from the form validation, duplicate actions, resources not found, broken elements, etc.
Unexpected Errors:These are the errors that are likely to indicate a bug in the application, such as unhandled exceptions which is unknown to the developer while developing the application.
Authorization Errors:When any of the users are trying to attempt to perform an action to which he/she does not have any access or is not authorized to use.
Mostly, all applications will have instances or the impact of each of these above error categories at some point of time while developing or accessing the application interface. But handling each error type/category appropriately is key to keeping users our customers/visitors without any issues.
What is Test-driven development?
Test-Driven Development (TDD) is a software development process in which the test cases are developed by the specialized developer i.e. QA to specify and validate what the code should perform. In other words, the test cases for each feature of the application are prepared and tested first and if the test cases may fail then the new code is written by the originated developer again in order to pass the test case requirements and make the code simple and bug-free for the production-ready app.
The test-driven development process consists below steps to be performed.
Add a test scenario
Run all test cases and see if any of the defined tests fail
Re-write the feature to make the codebase pass the defined test case
Run tests again and code refactoring
Repeat again
What is Unit Testing?
Unit testing is a type of software testing where the individual units or components of a software application are tested based on a specific set of pre-defined conditions.
The purpose of unit testing is to validate that each unit of the software codebase performs exactly as expected after the completion of the development. Unit Testing is can be done during the development of an application by the developers. Unit Tests consist of a section where the code can verify its possible correctness. A unit may be a component, individual function, method, variable, module, or whole object.
Any unit testing can be categorized into two different categories.
Manual testing
Automated testing
The unit testing is commonly performed in an automated manner but it may still be performed manually like testing the input fields. A manual approach to the unit testing may employ a step-by-step instructional document given by the specialized team of QA (Quality Assurance).
What is Cloud Computing and its Advantages?
The cloud computing allows one computer/system to get the benefits from the public/private shared resources and databases of computers connected to a single network. All the computation generally occurs through the cloud or the Internet connectivity.
Cloud computing is quite handy because we are able to store all our files and data on a remote database instead of being limited to local hard drives or storage devices. And this extends only to single files but also has a huge set of data, up to and including the complex programs or the software application.
There are some of the primary advantages of using cloud computing are given below.
Cost-saving
Prevention of the data loss
Extensive mobility and usability
Top-notch security configuration
Disaster recovery
Services on-demand
Access to the broad network availabilities
What are the popular clouds?
Cloud computing has been an essential part of the business and its complete digital transformation for many years now. Due to the surge in the popularity of remote work culture in recent times, these cloud services have become even more popular. These cloud computing services are very easy to use and configure and help us to save development/deployment time and energy by using their well-prepared services.
Below are some of the popular cloud services/platforms available.
Amazon Web Services (AWS)
Microsoft Azure
Alibaba Cloud
Google Cloud
IBM Cloud
What are the best editors/tools available for full-stack development?
There are tons of full-stack developer tools available in the world starting from the IDEs to the project management apps, you’ll find plenty of options to choose from. That is why it can get a little confusing for a developer to choose a specific tool. As the demand for full-stack developers increases so does the number of developer tools.
Below are some of the IDE/Tools available for full-stack development.
Visual studio code/WebStorm/Visual studio/Notepad
Github
Slack/Skype/Microsoft teams
Jira/Trello
ROR/Django/JavaScript
MySql/MongoDB/PostgreSQL/SQL Server
Docker
AWS/Microsoft Azure
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