TikTok Interview Questions — Page 12

TikTok·Software Engineer·Onsite - System Design / Architecture

May 2026

TikTok data engineering interview with a single deep-dive design question covering basically every corner of data warehouse architecture at once. No SQL required but the scope was massive and I felt like I was juggling five problems simultaneously.

Given an e-commerce marketplace with buyers, sellers, orders, order items, payments, and page view events, design a data warehouse model to support: daily session-to-purchase conversion rate, average order value, 7-day buyer retention by signup cohort, cancellation rate by seller, and daily GMV by category. Cover fact and dimension tables, grain, key columns, data types, partitioning and clustering, late-arriving events, deduplication, anonymous users, and slowly changing seller attributes. Justify your schema style and surrogate key choices.

“This was a lot to hold in your head at once.”

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TikTok·Product Manager·Onsite - Product Sense / Strategy

May 2026

TikTok PM interview focused almost entirely on a single meaty A/B testing scenario around in-app purchase pages for a mobile game. It was more analytical than I expected for a PM role, felt closer to a data science screen at points.

For an A/B test comparing two in-app purchase pages where Page A has a higher price but fewer buyers and Page B has a lower price but more buyers, what hypotheses would explain each page outperforming the other?
What primary and secondary metrics would you track for this A/B test, and why did you choose each one?
Walk through the statistical approach you'd use to determine significance in this experiment, and how would you verify the sample size is sufficient for adequate statistical power?
How would you factor a promotional mechanic like 'spend X amount and receive bonus Y' into your ROI calculation for the experiment?
Based on the results of this initial experiment, what follow-up experiment would you propose?

“This is where I spent most of my time and honestly felt pretty good about it.”

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TikTok·Machine Learning Engineer·Technical Phone Screen

May 2026

TikTok ML Engineer interview that went pretty deep into C++ internals, which I wasn't fully expecting for this role. The virtual function stuff caught me mid-stride and I had to think harder than I'd like to admit.

In C++, what is the difference between a virtual function and a pure virtual function? Walk through the syntax, explain how the vtable enables dynamic dispatch, and describe how overriding works in derived classes.
When does a class become abstract in C++, and can a pure virtual function still have a body or definition?
Should constructors or destructors be virtual in C++? What are the implications for resource management, and when would you use each in interface design?

“I knew the basics but fumbled explaining vtable mechanics under pressure.”

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TikTok·Software Engineer·Onsite - System Design / Architecture

May 2026

TikTok software engineer interview that leaned heavily on infrastructure and reliability concepts. The questions covered a pretty wide surface area, from Kubernetes basics to distributed systems debugging, so it felt less like a coding round and more like a system design and SRE-flavored session.

What is the difference between a Pod and a Deployment in Kubernetes, and what does a Service do?
Walk me through how you would debug a Pod that won't start. What steps do you take and which kubectl commands do you use?
Define SLO, SLA, and SLI. If your error rate is breaching the SLO, how do you respond and how do you prioritize?
A distributed service is seeing elevated request latency. Walk me through how you'd investigate across the network, load balancer, database, cache, and the service itself. What metrics do you check and what experiments do you run?
Compare SQL and NoSQL databases. In what situations would you choose NoSQL over a relational database?

“Felt pretty solid on this.”

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TikTok·Software Engineer·Onsite - Coding / Algorithms

May 2026

TikTok software engineer coding round with two algorithm problems back to back. Nothing too exotic but the tree question had a small wrinkle that slowed me down.

Given an array of strings, group all anagrams together and return the groups in any order.
Given a binary tree, return the values visible from the right side, top to bottom.

“Pretty standard once you see it.”

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TikTok·Data Scientist·Onsite - System Design / Architecture

May 2026

TikTok DS interview that was basically one massive system design question about ad selection. The scope was enormous and I felt like I was just barely keeping up the whole time.

Design an end-to-end ad selection system for TikTok that chooses among three advertiser types (gaming/CPI, e-commerce/CPA, branding/CPM) at impression time to maximize expected advertiser value while respecting budgets and pacing.
What features and models would you use to estimate P(install | ad, user, context) and P(purchase | ad, user, context), and how would you calibrate these for auction-time use?
How do you make scores from different ad objectives comparable at auction time, and what quality thresholds or user experience constraints would you apply?
How would you handle exploration vs. exploitation in this ad system, including cold-start for new advertisers and guardrails like frequency capping and fairness?
Walk through the auction mechanics you'd use, including bid shading, pacing control, and how multi-objective bidding interacts with second-price or VCG auctions.
How would you evaluate this system offline and online, detect feedback loops, and measure success beyond short-term revenue metrics like incremental ROAS and long-term engagement?

“This was the whole interview, basically.”

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TikTok·Software Engineer·Onsite - Product Sense / Strategy

May 2026

Interviewed for a bizops role at TikTok Shop, focused on category development. Single strategic question about the automotive vertical, which sounds narrow but actually opens up into a pretty broad conversation about platform risk and ecosystem fit.

How does the automotive category fit into TikTok Shop's broader ecosystem, and what are the key risks involved in building out this category?

“I spent the first part talking about why auto is interesting for TikTok Shop at all, short-form video is genuinely good for showing off cars and accessories, so the demand side made sense to me.”

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TikTok·Software Engineer·Onsite - System Design / Architecture

May 2026

TikTok SWE interview with a system design question on currency exchange. Not a lot of context in what I was given so I'm filling in some blanks from memory, but it was a solid design round that pushed me on edge cases I hadn't fully thought through.

Design a currency exchange system.

“I started with the obvious stuff, exchange rates, conversion endpoints, maybe a rate-fetching service pulling from some external provider.”

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TikTok·Data Scientist·Technical Phone Screen

May 2026

TikTok data scientist interview with a classic A/B testing scenario that sounds straightforward until you realize how many layers they actually want you to peel back. The question is less about the color change and more about whether you trust the experiment at all.

An A/B test changed a button color from green to red and retention dropped afterward. Stakeholders think the traffic split might be the real culprit. How do you investigate whether the allocation itself caused the retention drop, and what checks would you run before concluding the new color is actually harmful?

“I started talking about the retention metric too fast and the interviewer kind of steered me back with 'but how do you know the groups are even comparable?' which, fair point.”

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TikTok·Data Scientist·Technical Phone Screen

May 2026

TikTok data science interview with a brutal SQL question that had me second-guessing every window function I've ever written. One question, very technical, lots of edge cases baked in.

Write a single ANSI SQL query that identifies the top 10 countries by share of active creators whose posting frequency dropped more than 30% in the last 7 complete days compared to the prior 28 days. Use creators' local timezones for date bucketing, exclude test and deleted posts and non-active creators, and include per-country metrics: total active creators, dropping creators, share dropping, and median time between consecutive posts in the last 7 days. Define 'today' as 2025-09-01 using static literals only.

“This one took me a while to even parse.”

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