TikTok Data Engineer Interview Process

For the initial screening at TikTok, it begins with either submitting an application through their career portal or reaching out to a recruiter on LinkedIn. Once your resume is reviewed and you meet the basic qualifications, you'll move on to a phone screening.

During this call, they'll dive deeper into your background, qualifications, technical skills, and your interest in the Data Engineering role. 

Make sure you use this opportunity to demonstrate your fit for the position and learn more about what TikTok is looking for in candidates. Have a clear reason for why you’re applying to TikTok, as well as why you think you’d succeed there as a data engineer.

After you clear the initial screening, get ready for a deep dive! Now, the upcoming rounds can get intense; you'll spend about 4–5 hours solving real-world data engineering challenges. The main focus is on building a database for a new product. That means you'll be getting your hands dirty with tasks like designing data pipelines, running ETL processes, and shaping a solid database architecture.

We'd recommend you brush up on your SQL knowledge, get familiar with data modeling techniques, and practice thoroughly to demonstrate your hands-on experience in data engineering.

Let's discuss what you can typically expect in the technical rounds:

Technical Round 1 

This round typically kicks off with a mix of questions to gauge your skills across different areas. So, for instance, you might start with a medium-level SQL question, where you're asked to write a query to retrieve certain data from a database. Following that, you might tackle an easy Python coding question involving writing a simple script to manipulate data, implement a basic algorithm, or solve a straightforward problem.

While this round is mainly coding-base, sometimes, interviewers might dive deeper and ask follow-up questions. So, be ready for SQL query optimizations for time and space complexity.

Technical Round 2

This second 45-minute technical round delves deeper into your technical capabilities and explores your past experiences. You'll likely encounter another coding question, similar in difficulty to the one in the first round. However, the focus might be on a different aspect of data engineering or software development.

In addition to coding, you'll have a discussion about your resume and past projects. The interviewer may ask about specific projects you've worked on, challenges you've faced, and the solutions you've implemented. Typically, this segment will take up about 15 minutes of the interview. The remaining 25 minutes will again be dedicated to coding.

Example Questions

• Write a query that retrieves a list of all available lots from the 'lots' and 'bids' tables. Include the number of bids, the current lot price, and the current lot winner in the results.
• Implement a function to find and return the single element that appears only once in a sorted array of integers, where every other element appears twice.
• Write a SQL query to calculate the average salary of employees in each department of a company, along with the total number of employees in each department.
• Given a table 'orders' with columns 'order_id', 'customer_id', and 'order_date', write a query to find the number of orders placed by each customer in the year 2023.
• Implement a function to check if a given string is a palindrome (reads the same forwards and backwards), ignoring spaces, punctuation, and capitalization.
• Given a list of integers, write a function to find the maximum product of two integers in the list.

System Design 

This is a 60-minute interview where you'll be presented with an open-ended problem to design a system, always considering scalability. 

You'll need to analyze the problem, identify key components, and propose a system architecture that can handle large-scale usage. It will be followed by a detailed discussion on architecture, database selection, scaling, how you consider trade-offs, address potential challenges, and make sure the system stays reliable and works well even as it gets bigger.

Example Questions

• Design a data pipeline to ingest data from a livestream.
• Design tables and write SQL queries based on the provided functional requirements.
• Given a scenario where a company needs to process and analyze large volumes of sensor data collected from IoT devices, design a scalable data processing pipeline architecture.

Manager Round

It's a 60-minute session where you'll dive into your past projects and experiences; get ready to walk them through your role, the challenges you tackled, and the wins you achieved. They'll throw in some behavioral questions too, to see how you handle situations and work with others. 

There's usually a mini design problem that tests your understanding of cross Availability Zone data transfer and data security (Think—cloud architecture and ensuring data stays safe as it moves between zones). And of course, expect a deep dive into Spark. They'll want to know how well you know it, how you've optimized it, and your overall experience with it.

As you might have guessed, the technical interviews for data engineers at TikTok can get really complicated and challenging. We’d recommend practicing with a mock interviewer for a deeper dive. There are several data engineers at TikTok who provide great advice and guidance on how to deal with all the twists and turns this interview can take — and you can book a slot with them on Prepfully.

Apart from technical assessments, you can expect a behavioral round; just a heads up – this one is a bit different from the tech stuff. They'll hit you with situational scenarios, like challenges you might face on a project, and ask how you'd handle them. All they want to do is assess how you think on your feet and handle tricky situations. They're looking for qualities like problem-solving, leadership, and communication skills. So, be ready to share some stories from your past projects that show off those skills.

This is the last step in the process but equally important. First up, you'll tackle a case study; you'll typically be presented with a practical data engineering problem or asked to design a data system. For instance,

• Design a data pipeline for an e-commerce platform that tracks user interactions, processes orders, and provides real-time analytics for business insights.
• Design a real-time recommendation system for an e-commerce platform.

You'll need to really dig into the problem and understand what they're asking for. Then, come up with a solution (or multiple solutions) and explain why you're making specific design choices. And be ready to talk through those trade-offs, reliability, performance, and so on.

After this, you'll have the final interview with senior leaders or hiring managers. This one is straightforward enough; they'll dig into your fit for the Data Engineer role at TikTok. They will also want to know about your goals (both short-term and long-term) as well as prompt you to ask any questions you have about the role.

• How would you design a data pipeline to handle large volumes of streaming data on TikTok?
• What data processing frameworks have you worked with, and how have you optimized them for performance?
• Describe a time when you faced a data quality issue and how you resolved it.
• Can you explain the concept of data partitioning and how it can improve query performance?
• How do you ensure data privacy and security in your data engineering projects?
• How to resolve data skewness?
• What do you know about the key-value Database?
• What is your highlight project?
• Can you explain SQL window functions?
• How to iterate through substrings?
• What is the difference between star and snowflake schema, and what are their pros and cons?
• How would you retrieve the top 10 customers who watched the most video based on the duration watched?
• Write a program in Python to reverse a linked list.
• Write a program in Python to find the mirror image of a binary tree.