TikTok Software Engineer interview questions

102 Software Engineers have shared notes from their TikTok interviews, with the questions they were asked in each round. That is 37% of the 279 TikTok interview notes on Screna AI.

102 Software Engineer interview notes

TikTok·Software Engineer·Onsite - Behavioral / Leadership

Jul 2026
Behavioral round for a software engineer role at TikTok. Two questions, both pretty standard career and teamwork stuff, nothing too surprising but they did push for real examples.
  • Where do you see your career going in the next one to three years, and what draws you to this particular role and team right now?
  • Walk me through how you work with others on a team, especially when there's disagreement or you need to align on a technical direction. Give a specific example.

“I had an answer prepared but it felt a bit generic once I said it out loud.”

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TikTok·Software Engineer·Technical Phone Screen

Jul 2026
TikTok software engineer coding round, one algorithmic problem the whole session. Pretty standard sliding window territory but the details trip you up if you're not careful.
  • Given a text string and a pattern string, find all starting indices in the text where a substring of the same length as the pattern is an anagram of the pattern.

“Classic sliding window with frequency counts.”

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TikTok·Software Engineer·Technical Phone Screen

Jul 2026
TikTok software engineer interview that was pretty much a classic LRU cache problem. Nothing too surprising but there were a lot of follow-up angles they pushed on, so it wasn't just 'code it and move on'.
  • Design and implement an in-memory LRU cache with O(1) get and put operations. Walk through your data structure choices, how you maintain access order, and how updates to existing keys are handled.

“I went with the standard hashmap plus doubly linked list combo, which they seemed fine with.”

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TikTok·Software Engineer·Technical Phone Screen

Jul 2026
Coding interview at TikTok for a software engineer role. Two algorithm questions, both with follow-up discussions on complexity and design trade-offs. Pretty standard competitive programming territory but the extensions they asked about kept things interesting.
  • Given a binary grid where 1s are land and 0s are water, count the number of distinct island shapes. Two islands count as the same only if one can be translated to match the other; rotations and reflections are considered different. Then explain how you'd extend this if rotations and reflections also made islands equivalent.
  • Given an integer array and a window size k, find the maximum value in every contiguous subarray of length k. Implement a linear time solution and explain why it's O(n). Then compare it to a heap-based approach and discuss the trade-offs.

“The base version I got through fine.”

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TikTok·Software Engineer·Onsite - System Design / Architecture

Jul 2026
TikTok system design round, one massive question that basically covered every angle of a flash-sale ticketing system. The scope was genuinely intimidating and I left feeling like I'd only scratched the surface on half the topics.
  • Design a high-concurrency ticketing system for limited inventory (like a sold-out concert) that can handle millions of simultaneous purchase attempts without overselling. You need to cover admission control, inventory correctness, bot mitigation, idempotency, hot-key sharding, APIs, data modeling, caching, async messaging, consistency tradeoffs, failure handling, capacity planning, and monitoring.

“This was essentially thirteen questions wrapped in one.”

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TikTok·Software Engineer·Technical Phone Screen

Jul 2026
TikTok software engineering interview that went pretty deep into Python internals. Three questions, all technical, no fluff. Felt like they wanted to see if you actually understood the language or just knew how to use it.
  • In Python, what is the difference between mutable and immutable objects, and how does that distinction affect what happens when you pass them into functions or store them in containers?
  • How does a shallow copy differ from a deep copy in Python, and when would you use one over the other? What can go wrong with nested structures?
  • Can you explain Python's Global Interpreter Lock, how it affects multithreading versus multiprocessing, and when you'd choose threads, processes, or async I/O for a given workload?

“This sounds basic until you're mid-explanation and realize you're not totally sure how to describe what happens when you pass a mutable default argument to a function.”

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TikTok·Software Engineer·Technical Phone Screen

Jul 2026
TikTok software engineering interview that centered on a graph theory problem. Pretty standard algorithmic round but the follow-up questions about edge cases and complexity analysis kept it from being a cakewalk.
  • You're given an undirected graph as an adjacency list where adj[i] contains the indices of guests who know guest i. Can all guests be seated in at most two groups such that no two guests in the same group know each other? Return true or false, implement the algorithm, handle disconnected components, and analyze time and space complexity.

“This is bipartite checking, which I recognized pretty fast, but I fumbled the disconnected components part initially.”

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TikTok·Software Engineer·Technical Phone Screen

Jul 2026
Interviewed for an SRE intern role at TikTok and got hit with a LeetCode hard in a 30-minute live coding session. First ever technical interview and it did not go well.
  • Implement a basic calculator that supports addition, subtraction, multiplication, division, and nested parentheses (LeetCode 772 style).

“I froze.”

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TikTok·Software Engineer·Technical Phone Screen

Jul 2026
TikTok SWE coding round, just one linked list problem. Pretty standard stuff but worth knowing cold if you're prepping.
  • Given the heads of two singly linked lists, write a function that finds and returns the node where the two lists intersect, if one exists.

“Classic problem.”

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TikTok·Software Engineer·Onsite - Coding / Algorithms

Jul 2026
TikTok software engineer coding round, two algorithmic questions back to back. Nothing too exotic but the complexity analysis follow-ups were where things got real.
  • You're given a list of closed-open time intervals representing meetings on a single calendar. Find the minimum number of rooms needed so no two overlapping meetings share a room. Walk through your algorithm, justify the time and space complexity, and explain how you'd scale it for very large inputs.
  • Given the root of a binary tree, write an algorithm to check whether it is a complete binary tree. Cover the complexity, edge cases, and what test cases you'd write.

“Classic meeting rooms problem but they pushed hard on the 'very large inputs' part.”

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