Software engineering interviews at big tech companies can be daunting for even the most experienced developers. Given the ever-evolving nature of the field and complex technologies being developed every now and then, it is necessary for candidates to have a critical-thinking and problem-solving mindset for success.
Not to mention, companies like Google, Facebook, Amazon, etc have a strong culture of innovation and excellence. The competition at big tech is invariably fierce; only the most highly skilled, well-prepared, resilient, and ingenious candidates are likely to succeed.
If you are appearing for an interview at big tech in the near future, here's providing an overview of what you can expect during the interview process, along with tips for acing your interview.
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Software engineering interviews are designed to be rigorous and grueling—so as to test a candidate's technical prowess, get insight into their understanding of computer science concepts, and assess their industry knowledge.
Big tech companies are well-known for their challenging interview processes. Depending on the company you are applying to and the position you are targeting, the number of interview rounds will vary.
For instance, the interview process at Google typically comprises five rounds which includes a phone screening, a coding round, 1-2 technical interviews, and a systems design interview.
Facebook, on the other hand, has up to 6 rounds, starting with a virtual screening and a coding challenge, followed by four on-site interviews.
Some companies like Apple, Netflix, Uber, LinkedIn, etc also have different interview processes for different positions, such as back-end, full-stack, or front-end engineers.
Keeping minor differences aside, here's a general overview of what at big tech interview process looks like:
- The first round is a phone or video screening interview (some companies also assign a take-home exercise as part of the interview process)
- It is followed by one or more on-site interviews, which typically include a combination of technical (coding challenges and problem-solving questions) and behavioral (situational and hypothetical scenario-based questions), and system design rounds.
Let's explore the technical, behavioral, and system design rounds in detail.
Software Engineering Interviews at Big Tech
Software engineering interviews are designed to be rigorous and grueling—so as to test a candidate's technical prowess, get insight into their understanding of computer science concepts, and assess their industry knowledge.
Big tech companies are well-known for their challenging interview processes. Depending on the company you are applying to and the position you are targeting, the number of interview rounds will vary.
For instance, the interview process at Google typically comprises five rounds which includes a phone screening, a coding round, 1-2 technical interviews, and a systems design interview.
Facebook, on the other hand, has up to 6 rounds, starting with a virtual screening and a coding challenge, followed by four on-site interviews.
Some companies like Apple, Netflix, Uber, LinkedIn, etc also have different interview processes for different positions, such as back-end, full-stack, or front-end engineers.
Keeping minor differences aside, here's a general overview of what at big tech interview process looks like:
- The first round is a phone or video screening interview (some companies also assign a take-home exercise as part of the interview process)
- It is followed by one or more on-site interviews, which typically include a combination of technical (coding challenges and problem-solving questions) and behavioral (situational and hypothetical scenario-based questions), and system design rounds.
Let's explore the technical, behavioral, and system design rounds in detail.
Technical Interview
These interviews focus on the candidate's technical skills and knowledge, and will include questions pertaining to algorithms, data structures, systems design, and industry-specific knowledge. Candidates may also be asked to solve coding challenges or work through problem-solving exercises in a whiteboard setting.
Some commonly asked questions here include:
- Explain the differences between a stack and a queue
- How would you design a web crawler?
- Given a list of integers, how would you find the two numbers that add up to a specific target sum?
- How would you design a system that can handle a high volume of traffic?
- Explain the difference between a process and a thread
- How do you handle missing data when analyzing a dataset?
- Explain the concept of object-oriented programming
- How do you optimize the performance of a slow running query?
- Explain the concept of a closure in programming
- What is the difference between a GET and a POST request?
Behavioral Interviews
Behavioral interviews for software engineers at big tech companies are designed to assess the candidate's past experiences and how adept they are at handling difficult situations. These interviews are typically used to gauge a candidate's problem-solving prowess, their communication skills, and whether they can work as a team.
So, during the interview, you can expect a series of situational or hypothetical questions by interviewers to determine if you can think critically, communicate effectively, and have values and work ethics that align with the company's.
These questions may include:
- Can you tell me about a time when you had to solve a difficult problem?
- Tell me about a time when you had to work with a difficult team member
- How do you handle multiple priorities? Can you tell me about a time when you had to work under tight deadlines?
- Can you tell me about a time when you had to communicate a complex technical problem to a non-technical person?
- Tell me about a time you had to adapt to a new technology or programming language.
Behavioral interviews are a great opportunity for candidates to showcase their problem-solving skills, communication skills and ability to work under pressure. So, be prepared to give specific examples of past experiences to back your answers.
Systems Design Interviews
These interviews test the candidate's ability to design and architect large-scale systems. Candidates may be presented with a specific problem or scenario and asked to design a system, and explain their thought process and trade-offs.
A few questions you can expect here are:
- How would you design a distributed system for a web-based e-commerce platform that can handle high levels of traffic and ensure quick response times for users?
- How would you design a messaging system that can handle millions of messages per second and ensure delivery reliability?
- How would you design a system for real-time tracking and analysis of social media data?
- How would you design a scalable and fault-tolerant storage system for a large volume of user-generated data?
- How would you design an efficient and secure authentication and authorization system for a cloud-based service?
What are Big Tech Companies Looking for in Software Engineers?
Big tech companies are looking for innovative software engineers who showcase a combination of technical knowledge, industry knowledge, and strong problem-solving skills. They expect you to have in-depth understanding of trending programming languages and software development methodologies, as well as a strong grasp of algorithms and data structures.
First, it's important to understand the types of questions you can expect. For instance, Google is known for its brain teasers and puzzles, while Amazon focuses on "bar raiser" questions that test your problem-solving and critical thinking skills.
Here are a few examples of the types of questions that you may encounter during an interview with Google or Amazon:
Google Brain Teasers:
- You have eight balls, all the same size, but one weighs less than the others. How do you find the one that weighs less using a balance scale and only two weighings?
- You have a 3-gallon jug and a 5-gallon jug, and an unlimited supply of water. How do you measure exactly 4 gallons of water?
- Imagine you have a rope that burns in 60 minutes. How would you measure 45 minutes with this rope?
Amazon Bar Raiser Questions:
- You are given a list of a million integers, each from 1 to 10^9. How would you find the one integer that is not in the list?
- You are given a matrix of integers, where each value represents the cost of moving from that cell to an adjacent cell (up, down, left, or right). How would you find the cheapest path from the top-left corner to the bottom-right corner?
- You are given a large dataset and a query that returns the number of occurrences of a specific value. How would you optimize the query to run in the shortest possible time?
It should be noted that the actual questions can vary; they can be more open-ended and tricky, but the examples above should give you an idea of what you can expect.
In any case, here's key skills candidates should showcase during their interview:
- Ability to analyze and solve complex problems
- Understanding of trade-offs and edge cases
- Communication and collaboration skills
- Understanding of the company's industry and products
- Familiarity with relevant technologies and tools
- Experience working on similar projects or in similar environments
SDE Interview Preparation for Big Tech
To begin with, brush up on your knowledge of programming languages and software development principles, algorithms and data structures, systems design and architecture, and test-driven development and debugging techniques.
Next, you may use online resources; there is a plethora of software engineer interview preparation material available to help you prepare for your upcoming interviews at big tech companies.
- Websites like Leetcode, HackerRank are excellent to offer practice problems and participate in online coding challenges to help you hone your skills.
- You might also leverage books like "Cracking the Coding Interview" and "Programming Interviews Exposed" for more insight.
However, the best way to ensure ready-ness for your SDE interview preparation is to practice through mock interviews. You can find a friend or colleague to conduct a mock interview with you, or use online resources like Prepfully—which connect you with ex-recruiters and subject experts to help you practice interviews!
Good luck!