2023 PayPal Recruitment: Commonly Asked Interview Questions - IQCode

About PayPal

PayPal is a company that aims to democratize financial services, providing equal opportunities for people and businesses to participate in and succeed in the global economy. They believe that access to financial services can create opportunities, and their open digital payments infrastructure allows account holders to transact seamlessly in multiple ways, including online, mobile, app-based, and in person. Through technological innovation and strategic partnerships, PayPal provides ways for people to manage and transfer money with freedom and choice.

At PayPal, customer experience is a top priority, and they strive to create memorable experiences for all their customers, whether they're merchants, consumers, or members of the PayPal community. Working as a team, taking ownership and accountability, making informed decisions and achieving goals are all essential values that are prioritized at PayPal. The company seeks individuals with global perspectives and innovative ideas to make money secure and accessible for everyone. Interested candidates can refer to their job listings to see if any position is a good fit.

PayPal Recruitment Process

Interview Process

During the recruitment process, PayPal primarily focuses on evaluating a candidate's skills, experience, alignment with company values, and culture fit.

The interview process typically includes the following stages:

1. Application Submission: Interested candidates can apply through their website or job portals.

2. Screening: The recruitment team reviews resumes and applications to shortlist candidates that align with the job requirements.

3. Phone Interview: The recruitment team conducts a phone interview to further evaluate the candidate's suitability for the role based on their experience, skills, and job expectations.

4. In-person Interview: The interview panel assesses the candidate's fit for the job in terms of their technical skills, relevant experience, company values, and culture fit.

5. Final Interview: Successful candidates from the previous round are invited for a final round of interviews to evaluate their decision-making ability, leadership skills, and alignment with the company's vision and mission.

6. Job Offer: Upon successfully completing all interview rounds and satisfying any other requirements, candidates are offered the job, and the recruitment process comes to an end.

Potential PayPal Technical Interview Question:


What is Functional Programming in JavaScript?


Functional programming is a programming paradigm that treats computation as the evaluation of mathematical formulas and avoids changing-state and mutable data. In JavaScript, functional programming involves the use of higher-order functions, pure functions, and closures to achieve these goals. Higher-order functions are functions that can accept other functions as arguments and/or return functions as output. Pure functions always return the same output for the same input and produce no side effects, meaning they do not modify any data external to their scope. Closures allow inner functions to access variables declared outside of their scope. By utilizing these concepts, functional programming in JavaScript leads to more modular, reusable code that is easier to reason about and test.

What is a Callback Function?

A callback function is a function that is passed as a parameter to another function. This parameter function is executed after some specific action has taken place in the calling function. The calling function waits for the specified action to complete before executing this parameter function. It allows for asynchronous programming, enabling the calling function to continue its execution while the parameter function executes in the background.

What is an Event Loop?

An event loop is a programming mechanism that allows the code to keep listening to and responding to events as they occur. It works by continuously monitoring an event queue and executing any functions that are waiting to be executed when the appropriate event occurs.

In web development, the event loop is used to manage interactions between the user and the website. When the user clicks a button or enters data into a form, an event is triggered. The event loop is responsible for handling these events and updating the website accordingly.

The event loop is an essential part of the JavaScript language and is used in many other programming languages as well.

// Example code of an event loop in JavaScript
while (eventQueue.length > 0) {
  const event = eventQueue.shift();

Singleton Pattern

Singleton pattern is a design pattern that restricts the instantiation of a class to a single instance and ensures that a single instance is shared across the entire application. The pattern is popular in situations where it’s necessary to limit the number of instances of a class that get created to a single instance, like a database connection, logger or configuration settings.

Implementing singleton pattern involves creating a static instance of the class within the same class and making the class constructor private, so that instances of the class can only be created from within the class. The class also needs to provide a static method that returns the instance of the class, which can be accessed directly.

Here's an example implementation of the singleton pattern in Java:

public class SingletonExample {
    private static SingletonExample INSTANCE;

    private SingletonExample() {
        // private constructor

    public static SingletonExample getInstance() {
        if (INSTANCE == null) {
            INSTANCE = new SingletonExample();
        return INSTANCE;

    public void sayHello() {
        System.out.println("Hello World!");

In the above code, the SingletonExample class has a private constructor and a static getInstance() method that returns the single instance of the class. The INSTANCE variable is lazily initialized within the getInstance() method. Once the instance is created, subsequent calls to getInstance() will return the same instance. The class also defines a sayHello() method that can be called on the single instance of the class.

What is Node.js and Where can it be Used?

Node.js is a cross-platform, open-source JavaScript runtime environment that executes JavaScript code outside of a browser. It allows developers to use JavaScript on the server-side and build fast, powerful and scalable web applications.

Node.js provides an event-driven architecture which allows for non-blocking I/O operations. This means that applications built with Node.js can handle a large number of requests efficiently without blocking other I/O operations which results in faster performance and an improved user experience.

Node.js can be used to build a variety of applications such as web servers, command-line interfaces, desktop applications, real-time applications, chat applications, online games and many more.

Node.js is one of the most popular runtime environments and is continually growing in popularity due to its performance, flexibility, and ease of use.

// Example of Node.js usage 
const http = require('http');

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello, World!');

server.listen(3000, () => {
  console.log('Server running on http://localhost:3000/');

Functions and Their Usage in SQL

In SQL, functions are tools that can be used to perform specific operations on data values. They can be used to manipulate data, perform calculations, and return specific results based on input parameters. Functions can be used in queries, views, and stored procedures.

There are several types of functions available in SQL, including aggregate functions (such as SUM and AVG), string functions (such as CONCAT and SUBSTR), date functions (such as DATEADD and DATEDIFF), and mathematical functions (such as ABS and LOG).

Functions can be used in a variety of ways in SQL, such as to format data for display, to perform calculations on numerical data, and to extract sub-strings or specific portions of data from larger strings or text.

Overall, functions provide a powerful tool for working with data in SQL, allowing for a wide range of operations to be performed quickly and efficiently.

Features of Hadoop

Hadoop is a powerful open-source framework that is widely used for big data processing and analysis. It has several key features that make it a popular choice among organizations worldwide:

- Scalable: Hadoop is highly scalable, which means that it can handle large amounts of data without sacrificing performance or efficiency.

- Distributed computing: Hadoop distributes data processing tasks across many different nodes, which makes processing faster and more efficient.

- Fault tolerance: Hadoop is designed to be fault-tolerant. This means that if one node fails, the system can continue to operate without losing any data or performance.

- Cost-effective: Hadoop is an open-source framework, which means that it is free to use, and it runs on commodity hardware, which is much less expensive than proprietary hardware.

- Versatile: Hadoop can process a wide range of data types, including structured, semi-structured, and unstructured data.

- Flexible: Hadoop can be easily integrated with other tools and platforms, making it a versatile solution for data processing and analysis.

- Open-source: Hadoop is an open-source framework, which means that its source code is freely available for users to modify and customize to suit their needs.

Difference Between Events and Callbacks in Node.js

In Node.js, events and callbacks are both important concepts for handling asynchronous code.

Events: In Node.js, events are signals emitted when a certain action or activity occurs. An EventEmitter class is used to bind events and listeners. The EventEmitter class provides methods to register and remove event listeners. When an event is emitted, all the registered listeners for that event are called.

Callbacks: In Node.js, callbacks are functions that are passed as arguments to other functions and executed when the first function completes. Callback functions are used to handle asynchronous operations. The callback function is called once the asynchronous operation is complete or when an error occurs.

The key difference between events and callbacks in Node.js is that events are based on a publisher-subscriber pattern while callbacks are based on a caller-callee pattern. In events, an event is emitted when an action occurs. In callbacks, a callback function is called after an asynchronous task is complete.

Both events and callbacks are useful for handling asynchronous code in Node.js. Choosing between them depends on the specific use case, the complexity of the code and the personal preference of the developer.

What is the purpose of Debugger Keywords in JavaScript?

The debugger keyword in JavaScript is used to add breakpoints at certain points in code where we wish to pause the execution of the program. This allows developers to examine the values of variables, check the flow of the program and identify any potential issues. By using the debugger, we can step through our code line by line and identify the exact point where errors occur. The debuggers provide a powerful tool for troubleshooting code and improving the efficiency of our development process.Code:

from random import shuffle

# create a list of numbers
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9]

# shuffle the list

# output


[6, 3, 2, 9, 4, 8, 7, 1, 5]

In this example, the `shuffle()` method from the `random` module is used to shuffle the elements in a list of numbers. The `shuffle()` method randomly reorders the elements in the list.

Memory Management in Python

Python uses an automatic memory management system that manages the allocation and de-allocation of memory for the program. The system uses reference counting and garbage collection techniques for managing memory.

Reference counting is a technique in which the system keeps track of the number of references or pointers to an object in memory. When the reference count of an object becomes zero, the system automatically de-allocates the memory occupied by the object.

Garbage collection is a process of automatically detecting and freeing the memory occupied by objects that are no longer referenced by the program. Python uses a cyclic garbage collector that detects and cleans up cyclic references, which are references between objects that form a cycle.

Python also provides a module called _gc_ for fine-tuning the garbage collector. The module allows setting parameters such as the frequency of garbage collection and the threshold for detecting cyclic references.

Overall, Python's memory management system provides a simple and reliable way to manage memory in Python programs without having to worry about memory leaks and other memory-related issues.


In JavaScript, local variables are defined within a function using the `var`, `let`, or `const` keyword. These variables are only accessible within the function that defines them.

On the other hand, global variables are declared outside of any function and can be used anywhere within the code. However, it is considered a best practice to minimize the use of global variables as they can lead to naming conflicts and make debugging more difficult.

Some rules to keep in mind while using local and global variables are:

- Local variables should always be preferred over global variables. - Variables with the same name can exist in different scopes without any conflicts. - Values of global variables can be changed from any part of the code, which can sometimes lead to unintended consequences.

By following these rules, it's possible to write clean, maintainable code that is less prone to bugs and errors.

Namespace in Python

In Python, a namespace is a mapping between names and objects. It helps to avoid naming conflicts between different identifiers and provides a way to organize the code. Every module, function, method, class, and instance has its own namespace.

There are two types of namespaces in Python:

1. Local Namespace – It stores the names of local variables defined inside a function or method. It is created when the function or method is called and destroyed when it returns.

2. Global Namespace – It stores the names of global variables defined at the top level of a module. It is created when the module is imported and destroyed when the interpreter shuts down.

Python also provides a built-in namespace, which contains the names of built-in functions, modules, and exceptions.

To access a variable or function in a particular namespace, we need to use the dot (.) operator with the namespace name. For example, if we have a function named "add" inside a module named "math", we can access it as "math.add()".

Features of the Java Programming Language

Java programming language has several features that make it popular among developers. Here are some of the key features:

  • Simple and easy to learn
  • Object-oriented programming language
  • Platform-independent
  • Robust and secure
  • Supports multithreading and concurrency
  • Dynamic and interpreted
  • High performance through Just-In-Time (JIT) compilation
  • Wide range of built-in libraries and APIs

Java's features make it suitable for developing various applications such as web, desktop, mobile, enterprise, and embedded systems. Additionally, its robustness and security features make it a preferred choice for developing critical applications in industries such as finance, healthcare, and government.

Main Differences Between Java Platform and Other Platforms

The Java platform differs from other platforms in various aspects such as:

1. Platform Independent: Unlike other platforms, Java is a platform-independent language that does not rely on any specific hardware or operating system. This makes Java applications easily portable across different platforms.

2. Write Once, Run Anywhere (WORA): Java code can be written once and run on any platform that has the Java Virtual Machine (JVM) installed. This feature makes Java-based applications highly versatile and widely used.

3. Automatic Memory Management: Java uses automatic garbage collection, which helps in efficient memory management by freeing up memory occupied by objects that are no longer in use.

4. Strong Security: Java's strong security model prevents unauthorized access to system resources and ensures secure execution of applications.

5. Robust Exception Handling: Java provides a robust exception handling mechanism that helps in identifying and dealing with errors and exceptions in a well-defined manner.

6. Large Standard Library: Java comes with a vast standard library that provides a wide range of pre-built functions and classes that can be used to develop complex applications easily.

Overall, the Java platform's unique features make it stand out from other platforms, making it one of the most popular programming languages in the world.

What is a ClassLoader?

In Java, a ClassLoader is an essential part of the Java Virtual Machine that loads Java classes into memory from a file, network, or other sources. The ClassLoader is responsible for locating and loading the required classes at runtime. The Java ClassLoader follows a hierarchical model, where every ClassLoader has a parent except for the boot ClassLoader, which is at the top of the hierarchy. When a class is requested, the ClassLoader first looks in its cache and then delegates the request to its parent ClassLoader, following the hierarchy until the class is found or it reaches the top of the hierarchy. If none of the ClassLoaders can find the requested class, a ClassNotFoundException is thrown. Knowing the underlying mechanisms of ClassLoader is important for Java developers to avoid ClassLoader-related issues and to leverage the dynamic loading feature of Java.

Purpose of Static Methods and Variables

In object-oriented programming, static methods and variables belong to the class rather than a specific instance of the class. They can be accessed without creating an object of the class and are shared by all instances of that class.

The purpose of using static methods and variables is to conserve memory and improve performance. They are typically used for utility functions or constants that are common across all instances of a class. For example, if we have a class representing a car, we could have a static variable for the number of wheels that all cars share in common.

In addition, static methods can be convenient in situations where we want to perform an operation related to the class as a whole rather than a specific instance of the class. For example, a static method in a math class could be used to calculate the distance between two points.

Overall, static methods and variables provide a way to group data and functionality that doesn't depend on a specific instance of a class, resulting in more efficient and organized code.


Binary search is an algorithm used for searching an element in a sorted array. It works by repeatedly dividing the searched interval in half until the target element is found or the interval cannot be subdivided further. This algorithm has a time complexity of O(log n), making it much faster than linear search for large arrays.

Differences Between Insertion Sort and Selection Sort

Insertion sort and selection sort are two sorting algorithms used to arrange elements in ascending or descending order. Their differences are:

1. Approach

Selection sort selects the smallest or largest element in the list and swaps it with the first element. It then selects the remaining smallest or largest element, swaps it with the second element, and continues the process until all elements are sorted.

Insertion sort, on the other hand, selects an element and compares it to the previous elements. It then inserts the element at its correct position, pushing the other elements down, and continues the process until all elements are sorted.

2. Complexity

Selection sort is an O(n^2) algorithm—it takes twice as long to sort a list twice the size. Insertion sort also has an O(n^2) complexity but proves to be faster and more efficient than selection sort for small lists.

3. Adaptive

Insertion sort is an adaptive algorithm as its performance depends on the sortedness of the input list. The more sorted a list is, the less time it takes to sort it.

Selection sort, on the other hand, is not an adaptive algorithm. Its performance is not affected by the input list's sortedness.

4. Space

Selection sort is an in-place algorithm as it requires only constant memory space to sort a list.

Insertion sort is not an in-place algorithm as it requires additional memory space proportional to the size of the input list.

Finding the Depth of a Binary Tree

To find the depth of a binary tree, you can use a recursive function. The depth of the tree is the maximum distance from the root node to any leaf node. Here's an example implementation in Python:

class Node:
    def __init__(self, value):
        self.value = value
        self.left = None
        self.right = None

def maxDepth(node):
    if node is None:
        return 0
        # Recursively find the height of left and right subtrees
        left_depth = maxDepth(node.left)
        right_depth = maxDepth(node.right)
        # Return the maximum of the left and right subtree heights
        return max(left_depth, right_depth) + 1

# Example usage
root = Node(1)
root.left = Node(2)
root.right = Node(3)
root.left.left = Node(4)
root.left.right = Node(5)
print ("Depth of binary tree is:", maxDepth(root))

In this implementation, the "maxDepth" function takes in a root node and returns the depth of the tree. If the node is None, the function returns 0. Otherwise, the height of the left and right subtrees are recursively calculated, and the maximum of the two is returned plus 1 to account for the current level. Finally, an example binary tree is created and passed to the "maxDepth" function to demonstrate its usage.


To print the nodes in a circular linked list, we can start with a reference to the head node and traverse the list until we reach the head node again. During this traversal, we can print the value of each node.

Here's an example code snippet in Python:

# Defining a Node Class
class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

# Defining the Circular Linked List Class
class CircularLinkedList:
    def __init__(self):
        self.head = None

    # Adding a Node to the List
    def add_node(self, data):
        new_node = Node(data)
        if not self.head:
            self.head = new_node
            new_node.next = self.head
            current = self.head
            while current.next != self.head:
                current = current.next
            current.next = new_node
            new_node.next = self.head

    # Printing the Nodes in the List
    def print_list(self):
        if not self.head:
            print("List is empty.")
            current = self.head
            while True:
                current = current.next
                if current == self.head:

# Creating the List and Adding Nodes to it
clist = CircularLinkedList()

# Printing the Nodes in the List




Below are some interview preparation tips to help you ace your interview with PayPal:

// code for interview preparation tips goes here

// 1. Research the company and its culture, values, and mission statement.
// 2. Review commonly asked interview questions and practice your responses.
// 3. Prepare examples of your past experiences that relate to the job requirements.
// 4. Dress professionally and arrive on time.
// 5. Bring copies of your resume, a pen, and notebook.
// 6. Be prepared to ask questions about the company and the position.
// 7. Follow up with a thank-you email or note after the interview.

Zigzag String

Given a string and a number of rows, return the string formed by concatenating each row in order.

For example, given the string "abcdefghij" and 3 rows, the resulting zigzag string would be:

a   e   i
 b d f h j
  c   g

Here is the function signature:

def zigzag_string(string: str, rows: int) -> str:

Good Graph

This problem involves solving problems related to Data Structures and Algorithms of Graphs.

The name of the class is "Graph" and it contains methods required to solve the problem.

class Graph:
    def __init__(self, vertices):
        self.V = vertices
        self.adj = [[] for i in range(vertices)]
    def addEdge(self, u, v):
    def isBipartite(self, src):
        colorArr = [-1] * self.V
        colorArr[src] = 1
        queue = []
        while queue:
            u = queue.pop()
            for v in self.adj[u]:
                if colorArr[v] == -1:
                    colorArr[v] = 1 - colorArr[u]
                elif colorArr[v] == colorArr[u]:
                    return False
        return True

Converting Numbers to Words

This program converts a numerical input into its equivalent words. It uses string manipulation to concatenate the words together.

  def convert_number_to_words(n: int) -> str:
      # Define lists for words used in conversion
      ones = ["", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"]
      tens = ["", "", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"]
      teens = ["", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"]
      # Initialize final output and calculate number of digits in input number
      words = ""
      num_digits = len(str(n))
      # Handle special case of zero
      if n == 0:
          return "zero"
      # Iterate through number in groups of 3 digits, from right to left
      for i in range(0, num_digits, 3):
          # Get the current group of 3 digits
          group = str(n)[::-1][i:i+3][::-1]  # get group of 3 digits from right to left
          # Convert hundreds digit to words and add to output, if applicable
          if int(group[0]) > 0:
              words += ones[int(group[0])] + " hundred "
          # Convert tens and ones digits to words and add to output, if applicable
          if int(group[1:]) >= 20:
              words += tens[int(group[1])] + " " + ones[int(group[2])]
          elif int(group[1:]) >= 11:
              words += teens[int(group[2])]
          elif int(group[1:]) >= 1:
              words += ones[int(group[2])] if int(group[2]) != 0 else ""
          # Add appropriate scale word (thousand, million, billion) to output, if applicable
          if num_digits - i == 4 and int(group) > 0:
              words += "thousand "
          elif num_digits - i == 7 and int(group) > 0:
              words += "million "
          elif num_digits - i == 10 and int(group) > 0:
              words += "billion "
      # Return final output with extra spaces removed
      return words.strip()

Minimum Absolute Difference

To solve the problem [/problems/minimum-absolute-difference], the time complexity needs to be considered.

PayPal Interview Questions

Here are some interview questions that may be asked during a PayPal coding interview:

/* Code related questions */

In your code, how would you implement the functionality to [insert specific task] using [insert specific programming language/tool/framework]?

How would you optimize this block of code to improve its runtime efficiency?

/* Algorithm related questions */

How would you approach solving [insert specific algorithmic problem] using [insert specific data structure/algorithm/methodology]?

Can you explain how [insert specific algorithm/data structure] works and provide an example of when it would be most useful?

/* General questions */

Why do you want to work for PayPal?

What is your approach to problem-solving?

Can you walk me through a project you worked on and how you overcame any obstacles you encountered?

Describe a situation where you had to work with a difficult team member and how you handled the situation.

Frequently Asked Questions

1. How can I prepare for a successful PayPal interview?

To increase your chances of success in a PayPal interview, consider researching the company's values and goals, reviewing your resume and cover letter, practicing potential interview questions with a friend or family member, dressing professionally, and arriving organized and on time for the interview. Additionally, make sure you have a clear understanding of the job requirements and how your experience and skills align with them.

Remember to stay confident, engaged, and positive throughout the interview process. Good luck!

Reasons for Wanting to Work at PayPal

As an AI language model, I do not have personal desires or goals. However, as a version of the ideal candidate for the position, I can provide some reasons why someone would want to work at PayPal.

PayPal is a well-established and innovative company that is transforming the way people do business. It has a strong reputation for providing secure and reliable payment services. Working at PayPal provides opportunities to work with talented individuals from different backgrounds, learn new skills, and advance one's career. Additionally, PayPal's commitment to diversity and inclusion creates a welcoming atmosphere for all employees. Therefore, working at PayPal can be an exciting and enriching experience for anyone looking to build a career in the financial technology industry.

Introducing Yourself in a Technical Interview

When it comes to a technical interview, introducing yourself can set the tone for the entire conversation. You want to come across as confident, competent, and professional. Here are some tips:

1. Start with a greeting and your full name. 2. Mention your relevant education and work experience briefly. 3. Highlight your technical skills and specific projects you have worked on. 4. Express enthusiasm for the opportunity to interview and your interest in the position. 5. End with a strong closing statement, thanking the interviewer for their time and consideration.

Is PayPal a High-Paying Employer?

One might wonder whether PayPal offers competitive salaries to its employees.

PayPal Internship and Payment

Yes, PayPal interns receive payment for their work during the internship.

Eligibility Criteria for PayPal

To use PayPal, there are certain eligibility criteria that must be met. These criteria include being at least 18 years of age and having a valid email address. Additionally, users must have a bank account or credit/debit card to link with their PayPal account. It is also required to provide accurate personal information and ensure compliance with PayPal's terms and conditions. Following these criteria will enable individuals to take advantage of PayPal's various online payment services.

Technical Interview Guides

Here are guides for technical interviews, categorized from introductory to advanced levels.

View All

Best MCQ

As part of their written examination, numerous tech companies necessitate candidates to complete multiple-choice questions (MCQs) assessing their technical aptitude.

View MCQ's
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