PayTM Interview Questions

Abbreviated for Pay Through Mobile, PayTM is an Indian technology company that has its headquarters in Noida. This brand focuses on financial services, e-commerce, and digital payment systems. Currently, the app is available in more than ten Indian languages. On this platform, you can easily avail a gamut of services, including mobile recharge, event bookings, utility bill payments, travel booking, and much more. Through the PayTM app, you also get an in-store payment option through a QR code. Considering the technicality behind managing the app and keeping its functionality up-to-date, there is a constant demand for skillful software engineers at PayTM. Employees at this firm get to work in a fast-paced environment and create valuable products, thus, experiencing the utmost exposure. So, if you’re ready to be a part of this company, MindMajix brings you a list of the latest PayTM interview questions with answers for you to read through and prepare for the interview. 

• PayTM Recruitment Process
• PayTM Technical Interview Questions
  • Freshers
  • Experienced
• PayTM Coding Interview Questions
• PayTM Leadership Principles
• Tips to Crack PayTM Interview
• FAQ for PayTM
• Conclusion

Top 10 Frequently Asked PayTM Interview Questions

1. Briefly describe the singleton design pattern.
2. What do you know about virtual memory?
3. Can you explain namespaces in Python?
4. Define Unix kernel.
5. What is DHCP? State its advantages and disadvantages.
6. What are the features of Hadoop?
7. What do you know about a bug's life cycle?
8. Write a C++ function to showcase all nodes in a circular linked list.
9. Define macros in C/C++. Give an example.
10. In an integer array, how can you get matching elements?

PayTM Recruitment Process

The interview process at PayTM begins with you applying for the job. And then, an interview will be scheduled with you if you turn out to be a suitable candidate for the vacancy. Once you’re shortlisted, you will have to undergo different processes and a series of interviews.

• Online Coding Round

This online coding round ranges anywhere between easy to medium when it comes to complexity and critical analysis of your problem-solving competency. Usually, in this round, you will have to answer questions pertaining to data structures and algorithms on varying platforms, such as HackerEarth, Cocobues, Hackkerank, and more. This round can last anywhere between 60-70 minutes. You will have to use your problem-solving skills and understanding of data structures and algorithms to clear the round. Furthermore, if you have a competitive coding experience, it will be a plus point for you.

• Technical Interview Round

This round comprises almost four to six in-person interviews. You will be asked to use a whiteboard or a HackerRank to solve the questions and challenges. Every interview may include 5-10 minutes of discussion about your past work experience. You may also have to answer behavioral and situational interview questions. And then, you will be asked a series of data structures and algorithms questions. To stand out in this round, make sure you are well-versed in the development of distributed systems, working with APIs, cloud-based technologies, and SQL queries. Apart from this, get ready with selected programming languages, object-oriented programming concepts, networking, operating systems, and database management systems.

• HR Interview Round

This Human Resource round tries to comprehend whether you are a cultural match for the company. To ace this round, you must study the brand and its products thoroughly. You may have to answer puzzle-based questions that are meant to evaluate your intelligence level. The questions are also designed to check how well you can adapt to challenging and awkward situations.

PayTM Technical Interview Questions

After getting to know the PayTM interview process, the next step is to make you familiar with the types of interview questions asked here. Below-mentioned are the latest PayTM interview questions for freshers and experienced, along with coding questions. Let’s have a look further.

PayTM Technical Interview Questions for Freshers

If you’re a fresher and would like to get a job at PayTM, here is the list of interview questions that you cannot afford to ignore.

1. What do you know about web applications?

Also known as a web app, a web application is software that runs on a web server in contrast to the computer-based software app that runs on the Operating System (OS) of a device. To access a web app, you will need a web browser and an active network connection. The user (also called a client) gets to access services from an off-site server that a third party hosts in these apps. These servers are generally developed on a client and server architecture. 

Are you looking forward to becoming a Core Java Developer? Check out the Core Java Training and get certified.

2. Briefly describe the singleton design pattern. 

It is a software engineering design pattern that limits the instantiation of a class to one single instance. This is beneficial when just one object is required to coordinate system-wide actions. The singleton is regarded as one of the most important design patterns. Since creating a different database connection for every object is an expensive affair, we sometimes only need one instance of the class, like one database connection that is shared by different instances. In the same manner, instead of developing different managers, an app can have one error or configuration manager that can handle all the issues. 

3. What do you know about virtual memory?

Virtual memory is a memory type that is created on a storage device for some time period. When the RAM of a computer gets drained because of multiple processes running simultaneously, virtual memory is created. The OS makes a part of the storage disc available to be used as RAM. Significantly, virtual memory is slower as compared to primary memory as the processing power gets used by moving data and not by performing instructions. When a computer has to use virtual memory, latency increases. The OS uses swapping to move data between virtual memory and RAM. 

4. Can you explain namespaces in Python?

The namespace is a significant notion for structuring and organizing code that is specifically useful in bigger projects. To make this entire process simpler, a namespace is used that helps manage the names in a program with ease. Through this, you can make sure that names are diverse and not misunderstood.  

5. Define Unix kernel.

The Unix kernel is considered the heart of the OS. It helps connect to the memory, processor, and I/O management along with hardware devices. The kernel handles user requests through system calls that shift the process from a user to kernel space. Each time a user process makes any system call, like open(), exec(), read(), and more, a context switch takes place. A context switch is referred to a mechanism for changing the processes’ state. A process can be halted until the system call gets completed, or it can even continue.  

6. How can you define marshaling?

Marshaling is referred to the conversion of an object’s memory representation into a format that can be transferred or saved to other software apps. This process converts an object into a serialized form that lets faraway objects communicate with each other.  The object of marshaling is to have a similar object present in one operating program be available in another. 

7. Do you understand anything about system calls?

Through a system call, a computer program or a piece of software requests a service from the kernel of the OS where it is executing. This is a way for the program to interact with the OS. The Application Program Interface (API) is generally used to offer services from the OS to user programs. It further acts as a link between the OS and the process, thus, letting user-level programs request services from the OS. System calls, so far, are the only way that enables entry into the kernel system. 

8. In JavaScript, what is functional programming?

Functional programming is the programming paradigm that helps deal with mathematical functions. Here, the focal point is to write pure and sophisticated functions. Considering that JavaScript is a multi-paradigm language, you can integrate several paradigms in a single code piece. At the same time, you can use functional programming, procedural, and object-oriented paradigms with JavaScript. 

9. Mention a key difference between computer software and a computer program.

The key difference between computer software and a computer program is that the former is a collection of different programs used to complete different tasks. On the other hand, the latter is a set of instructions that are expressed in a programming language. A program can be software but not vice versa. 

10. Which is the best SDLC model?

Accordingly, Agile is the best SDLC model and also the one that is prevalently used in the IT industry. The reason behind it being the best is that it is a hybrid of iterative and incremental approaches and works accurately in a flexible environment.

Check Out: SDLC Interview Questions and Answers

PayTM Technical Interview Questions for Experienced 

If you are an experienced person and are looking for a job at PayTM, here is a list of interview questions to prepare. 

11. What is DHCP? State its advantages and disadvantages.

DHCP is Dynamic Host Configuration Protocol. It has a server and client architecture. 

Advantages of DHCP:

• It is easy to set up, and it assigns IP addresses automatically to request clients. This results in the decreased time needed to manually configure IP addresses.
• It prevents incorrect or twice assignment of IP addresses; thus, it doesn’t cause any dispute in IP addresses.
• It is advantageous for mobile users as the newer network sends the associated configuration parameters instantly.
• The deployment doesn’t result in extra expenditure.
• It can handle several things, including super scopes and multicast.
• It simplifies the entire network administration.

Disadvantages of DHCP:

• A relay agent is needed to make sure the DHCP server handles every communication for both network segments since DHCP packets cannot traverse routers. 
• Upon the assigning of new IP addresses, the machine name remains constant.
• The server of DHCP can get unauthorized access to the IP addresses through credential details submission because there is no secure method for client authentication.

12. What are the advantages and disadvantages of a star topology in a computer network?

In a computer network, the spoke hub distribution concept gets used in the star topology. Every host in the star network is linked to a central hub. In the simplest form, a single hub works as a message route. Star network is one of the most commonly used computer network topologies. 

Advantages of Star Topology

• It can be examined, set up, and changed with ease.
• Transferring, uninstalling, and adding devices is simple.
•  The nodes that have failed get affected. Others remain operational.
• High performance can be accomplished with little network traffic and a small number of nodes. 

Disadvantages of Star Topology

• If the concentrator or hub fails, the linked nodes get disabled.
• A lack of accurate termination or a damaged cable can bring the network offline.
• Setting up a star topology is expensive.
• The capacity of the hub comprehends the performance.
• There could be substantial delays in buses because of the heavy network load.

13. What are the features of Hadoop?

Some of the Hadoop features are as follows:

• OpenSource: Since it is open-source, Hadoop can be used free of cost. The source code is available online so that anybody can read and edit it according to their needs.
• Flexibility: Hadoop is developed in a way that it can effectively handle any dataset type, including structured, semi-structured, and unstructured. This means that it can evaluate any data type, irrespective of the form; thus, making it completely adaptable. It turns out to be extremely advantageous to organizations as it lets them process large sets of datasets instantly. As a result, businesses can use Hadoop to evaluate essential insights from data sources like email, social media, and other sources. The flexibility of Hadoop lets it be used for fraud detection, data warehousing, log processing, and more.

• Fault Tolerance: Hadoop is something that runs on commodity hardware that can crash at any time. In Hadoop, data is duplicated across several DataNodes in a Hadoop cluster, making sure data is available even if one of the systems fails. If a machine faces a technical issue, you can easily read the data from that specific machine. Since the data is replicated or copied by default, it can be read from other nodes available in a Hadoop cluster.

• High Availability: With fault tolerance, high availability can be ensured in a Hadoop cluster. If any of the DataNodes fails because of fault tolerance, the data can be recovered from other nodes where the same data is replicated. The Hadoop cluster that has the highest availability has two or multiple Name Nodes, such as Passive NameNode and Active NameNode. If one fails, the other will take over.

• Clusters with High Scalability: Hadoop is an extremely scalable model. A huge amount of data is split across varying low-cost devices in a cluster. It gets processed in parallel. As per the business needs, the number of nodes or computers can be decreased or increased.

• Cost-Effective: Contrary to traditional relational databases, which need expensive CPUs and high-end hardware to deal with big data, Hadoop leverages inexpensive commodity technology. It results in a pocket-friendly paradigm.

Check Out: Hadoop Interview Questions

14. What do you know about schedulers? How do they work in an OS? List down different scheduler types found in OS. 

Schedulers are special computer programs that regulate how processes get scheduled in different ways. Their major responsibility is to comprehend the jobs that should be entered into a system and which processes should be executed. 

Here are three types of schedulers in an OS:

• Long-Term Scheduler: Also known as a task scheduler, it comprehends which apps can be accepted for processing into a system. Before a process is executed, it is chosen from the ready queue and is loaded into memory. The process then gets loaded into memory for CPU scheduling. The primary goal of the job scheduler is to deliver a well-balanced mixture of operations, including CPU-bound workloads and input/output. 
• Medium-Term Scheduler: This is used to shift programs in the primary memory. It frees the RAM that processes consume. This results in multiprogramming reduced to a minimum. The medium-term scheduler manages the swapped-out processes. 
• Short-Term Scheduler: It is also called a CPU scheduler, and its objective is to enhance the system performance as per the set of predetermined criteria. It is the process of transition. The CPU scheduler chooses one of the ready-to-run processes and assigns CPU time to the same. 

15. How do you differentiate between local variables and global variables?

We can differentiate between global variables and local variables on the basis of their features. 

Global variables have the below-mentioned features:

• Variables that are defined outside of a specific function or in the global space are called global variables.
• Any function can modify and access the global variable’s value from anywhere in the program.
• In case a variable is given a new value, it is implicitly local, and we can designate it as ‘global.’ 

Local variables have the below-mentioned features:

• Any variable that is declared in a function is known as a local variable. It only exists in the local space and not in the global space. 
• Variables can only be accessed in the local body. 
•  If, anywhere in the function, a variable gets a new value, it is regarded as local.

16. What are storage classes in C? What are storage classes in C?

Storage classes can be used to define the properties of a function or a variable. During a program’s execution, the durability, visibility, and scope of a variable help track its presence. There are four different storage classes in the C programming language, such as:

• Auto: In this class, every variable that is supplied inside a block or a function gets stored here by default. Auto variables can be used only within the function or block wherein they were defined and not outside them. However, you can access them outside of the scope through pointers that point to a memory address where a variable is stored. Whenever declared, an auto gets a garbage value by default. 
• Extern: With the “extern” term, you can comprehend that the variable gets defined outside of a block wherein it is used. It gets a value in any other block, which can be updated or overwritten in another block. We can make an ordinary global variable an extern through the ‘extern’ keyword before its definition or declaration in any block or function. This simply means that instead of creating a new variable, we get to only access and use the global variable. With the extern keyword, we can make a function and variable more visible. 

• Register: This storage class is used to declare register variables, which are the same as auto variables as far as functionality is concerned. The primary difference here is that the compiler attempts to store the variable in the register of the CPU in case there is a free registration. Otherwise, the data gets stored only in memory. To define some variables that can be accessed often throughout the program, the register keyword is used. 

• Static: This type is used to define static variables, which are prevalently used in the C language. Static variables are used to preserve the value even once they are removed from the scope. Thus, it is safe to say that they are initialized only once and exist till the program comes to an end.

17. What do you know about a bug's life cycle?

Also known as the defect life cycle, the bug life cycle is a process used to advance the defect via several phases of its existence. This lifetime starts when a tester reports a problem and ends when that issue is fixed. In a defect workflow, the following fault states can take place:

• New: A defect gets this status when it is documented for the first time.
• Assigned: When a tester has filed the bug report, their lead approves and assigns the same to the programming team.
• Open: The developer begins evaluating and fixing the issue.
• Fixed: Once the required code patch is done, the developer gets to mark the issue as ‘fixed.
• Pending Retest: After resolving the issue, the developer offers the tester a unique code to retest. Since the software testing is pending from the tester’s end, it gets marked as ‘pending retest.
• Retest: At this stage, a tester gets to retest the code to ensure that the problem is resolved.
• Reopened: If the issue still persists, the status gets changed to ‘reopened’, and the entire life cycle gets repeated.
• Verified: Once the issue is fixed and the tester has retested the code, it gets verified.
• Closed: A ‘closed’ tag is used when the issue doesn’t exist any longer. 

18. What are the different layers in the OSI model?

Open Systems Interconnection (OSI) was founded in 1984 by the International Organization for Standardization (ISO). The OSI model has seven layers with different functions for every tier. However, these layers work together to transfer data across the world from one person to another. The layers are:

• Physical Layer: This one is the lowest layer and is responsible for establishing a physical link between different devices. The layer stores bits of information and sends individual bits from a node to the consecutive one. The physical layer gets data and turns the same into 0s and 1s before it sends the data to the next layer. 
• Data Link Layer: This layer is responsible for transporting the message from one node to the next. The primary function of this layer is to make sure the data transferred between nodes is error-free. There are sublayers to the data link layer, such as Control of Media Access (MAC) and Control of Logical Links (LLC).

• Network Layer: This one is liable for transferring data between hosts that are linked to varying networks. It also handles packet routing, which is a process of choosing the shortest path among various to send a packer. The network layer includes the IP addresses of the sender and the receiver in the header. 

• Transport Layer: This layer offers services to the application layer. Herein, the segments are regarded as data units. The transport layer is responsible for delivering the message from start to finish. This layer identifies successful data transmission. And, in case of a mistake, it re-transmits the data.

• Session Layer: This one is in charge of creating connections, guaranteeing security, maintaining sessions, and authenticating users.

• Presentation Layer: In this layer, the data is obtained from the application layer and processed so that it can be delivered across the entire network in the right format.

• Application Layer: This is at the top of the OSI model and is integrated by network applications. This layer generates the information to be transmitted through the network. It also works as a window through which app services can connect to the network, and the information is displayed to the user. 

19. What do you know about socket programming? List down its advantages and disadvantages in Java. 

Socket programming is referred to as a method that allows two network nodes to communicate with each other. One socket monitors the traffic on a certain port at an IP address while the other is connecting to it. 

Advantages of Java Sockets

• Sockets are plentiful and adaptable. For regular communications, socket-based programming is easy to develop.
• Sockets cause low network traffic. Unlike CGI scripts and HTML forms, Java applets can send updated data. 

Disadvantages of Java Sockets

• Security limitations could be difficult at times.
• Socket-based connections are limited to the transfer of raw data packets between different programs. 
• There are restrictions in the reusability as data formats and protocols are specific to the application. 

20. Can you explain the modularization concept?

Modularization comes up when the functionality of a program is broken down into different, independent modules. Each of these modules carries the information required to execute only a part of the intended capability. To put it simply, this practice helps divide the program into small modules so that you can deal with them separately. Through modularization, we can add smaller and independent modules to a program without being affected by the complications of the other functionalities of that program. 

PayTM Coding Interview Questions

For those who are into coding, these questions with answers will be useful in the interview. 

21. Write a C++ function to showcase all nodes in a circular linked list.

A C++ function that can showcase all nodes in a circular linked list is as follow:
// A C++ Method for displaying all the nodes in a Circular linked list 
void displayCircularList(Node* root)
{
Node* a = root;
/* Provided circular linked list has at least one node, traverse the list*/
if (root) {
// Display all the nodes until the first node appears again
do {
cout << a -> val << " ";
a = a -> next;
} while (a != root);
}
}

22. What are callback functions in JavaScript? Give an example.

A callback function is one such function that gets input from another function and is called from within the outer function to complete the operation or routine. Here is an example of the same:

function cityCallout(city) {
alert('Welcome to' + city + '!');
}
function foo(callback) {
 var cityName = prompt('Please input the name of the city here:');
 callback(cityName);
}
foo(cityCallout);

23. Define macros in C/C++. Give an example.

Macros are preprocessor directives that can be replaced at the time of compiling. As a result, in a program, a macro is named a section of code. This name is substituted by the compiler with a real code piece. One disadvantage of macros is that they change the code instead of function calls. 

#include <bits/stdc++.h>
// Macros can be defined as shown below
#define ADD (2 + 1)
#define SUB (2 - 1)
#define MUL (2 * 1)
#define DIV (2 / 1)
// Main function of the C++ Program
int main()
{
cout << "The value of the sum of the given numbers is: " << ADD << "\n"; 
cout << "The value of the difference of the given numbers is: " << SUB << "\n";
cout << "The value of the product of the given numbers is: " << MUL << "\n";
cout << "The value of the division of the given numbers is: " << DIV << "\n";
 return 0;
}

24. How can you reverse a string in Java?

In Java, to reverse a string, we will first have to declare the string. And then, take the length of that string and loop through the string’s characters. Next, we will have to add those characters in reverse order in a new string.

String str = "hello";
String reverse = "";
int length = str.length();
for (int i = 0; i < length; i++) {
reverse = str.charAt(i) + reverse;
}
System.out.println(reverse);

25. How will you determine if a string is a palindrome?

When the string stays just the same on reversing the character’s order in that string, it is a palindrome. It can easily be achieved by reversing the original string first and checking whether the reversed string is equal to the original. 

if (str.equals(reverse)) {
System. out.println("Palindrome");
} else {
System.out.println("Not Palindrome");
}

26. How will you find out if the given two strings are anagrams?

We can ensure that two strings are anagrams in case they comprise the same group of characters in several sequences. 

boolean anagrmstat = false;
if (str.length() != reverse.length()) {
System.out.println(str + " and " + reverse + " not anagrams string");
} else {
char[] anagram1 = str.toCharArray();
char[] anagram2 = reverse.toCharArray();
Arrays.sort(anagram1);
 Arrays.sort(anagram2);
 anagrmstat = Arrays.equals(anagram1, anagram2);
}
if (anagrmstat == true) {
System.out.println(" anagrams string");
} else {
System.out.println(" not anagrams string");
}

27. In an integer array, how can you get matching elements?

To get the matching elements, we will have to declare an array. Next, we will nest a few loops to compare the numbers with the ones present in the array. We will then print the matching elements. 

int[] a = { 1, 2, 3, 4, 5, 1, 2, 6, 7 };
for (int m = 0; m < a.length; m++) {
for (int n = m + 1; n < a.length; n++) {
if (a[m] == a[n])
System.out.print(a[m]);
}
}

28. How to swap two numbers without the third variable?

For this, the first step is to declare two variables and then initialize those variables with values. Make ‘b’ the sum of these two numbers. Then, minus the ‘b’ (sum) from a; thus, a is swapped. Next, minus a from ‘b’ (sum); thus, b is swapped. 

int a = 10;
int b = 20;
b = b + a; // now b is sum of both the numbers
a = b - a; // b - a = (b + a) - a = b (a is swapped)
b = b - a; // (b + a) - b = a (b is swapped)

29. How can you discover the factorial of an integer?

public static long factorial(long n) {
if (n == 1)
 return 1;
else
return (n * factorial(n - 1));
}

30. How to integrate the insertion sort algorithm?

To do so, we will assume that the first element in an array has to be sorted. The second element will be stored differently in a key. This will sort the first two elements. Then, we can take the third element and compare it with those on the left. This process will continue until we get to a point where the array can be sorted. 

int[] a = { 1, 2, 7, 6, 4, 9, 12 };
for (int m = 1; m < a.length; m++) {
int n = m;
while (n > 0 && a[n - 1] > a[n]) {
int k = a[n];
a[n] = a[n - 1];
a[n - 1] = k;
n--;
 }
}

PayTM Leadership Principles

Here are some leadership principles being followed at PayTM that you should be wary of:

• Push boundaries: People at this company think differently. They find new ways to innovate and leverage technology to streamline everything.
• Entrepreneurial spirit: They set objectives and create plans to achieve them. They eradicate barriers and let curiosity be the guiding force. 
• Do great things fast: They concentrate on executing flawlessly. They work together effectively as a team.
• We before me: The team at Paytm is committed to solving real problems. They learn from failures and celebrate successes together.
• Communicate: They bring the best ideas by communicating with like-minded people. They brainstorm, speak up, and bring out the best product.
• Sharing is growing: They don’t stop themselves from sharing a good idea. They encourage every idea that helps add value to a new feature or product. 

Tips to Crack PayTM Interview

• Increase your speed: Test yourself to see how quickly you can solve coding problems and questions. This will help you enhance the overall reasoning frameworks and skills for problem-solving.

• Maintain a positive outlook: Mainting a welcoming and positive attitude is always advantageous. You must introduce yourself with utmost confidence. Also, make sure you begin the conversation on a favorable note.

• Demonstrate your experiences: You must share your experiences and stay ready to showcase leadership, academic, teamwork, and professional success along with problem-solving and communication abilities.

• Know yourself: You must be familiar with your weaknesses and strengths. Make sure you learn how to put your talents and experiences in a qualified way. Once in a while, during the interview, put forth an example that will help you stand out. 

PayTM Interview Frequently Asked Questions

1. Is the PayTM interview hard?

The questions asked in a PayTM interview range between moderate to difficult levels. 

2. How many rounds will be there in a PayTM interview?

There will be three rounds that you will have to go through to clear the PayTM interview. These rounds comprise an online coding round, a technical interview round, and the HR interview round. 

3. What is the full form of PayTM?

Pay Through Mobile is the full form of PayTM.

4. What are the advantages of working at PayTM?

There is plenty of benefits you can get when employed at PayTM, such as team outings, health insurance, job training, soft skill training, free transport, child care, education assistance, free food, and more. 

5. What is the basic salary at PayTM?

On average, you can earn anywhere between Rs. 2,50,581 to Rs. 11,00000 a year, depending on your position and experience. 

Conclusion

Preparing for a PayTM interview is not a difficult task, given that you are equipped with the right set of resources. Having said that, this post comprises all the latest PayTM interview questions and answers you can read through and prepare yourself well. Are you looking forward to becoming a Core Java Developer? Check out the Core Java Training and get certified.