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TikTok·Software Engineer·Technical Phone Screen·Junior

JuniorPrefer not to say
Jun 2026Remote

Summary

First round technical screen for a backend SWE role at TikTok, and it was genuinely one of the stranger interviews I've heard of. The interviewer showed up with half her face visible on camera, skipped any introduction, grilled me hard on internship work I had limited context on, threw a LC Hard at me, and then refused to share anything about her own background when I asked. Ended with feedback that my project work was 'too shallow', which, sure, maybe, but the whole thing felt off.

Questions Asked (2)

Q1

Walk me through a project you worked on during your internship. Why did your team design the service the way they did?

Technical Trade-offsAdaptability & Ambiguity
Author's notes

This went sideways fast.

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AI HintsAI Generated

Suggested Approach

Choose a project where you can clearly articulate the problem, constraints, and trade-offs that drove the design. Focus on explaining why the team made specific architectural or technical decisions, not just what was built. Highlight your individual contribution and how you navigated ambiguity.

Pro tip: Emphasize the constraints (e.g., latency, scale, cost) that forced trade-offs, and show you understand the 'why' behind decisions even if you didn't make them. This demonstrates systems thinking and maturity beyond just coding.

1. Set the context

Briefly describe the project, your role, and the team's goal. Mention the scale and any key constraints (e.g., latency, throughput, budget).

2. Explain the problem and requirements

Outline the core problem the service solved and the functional and non-functional requirements (e.g., scalability, reliability, cost).

3. Describe the design and alternatives

Walk through the chosen architecture and the alternatives considered. Explain why the team chose this design over others, referencing trade-offs.

4. Highlight your contribution and challenges

Detail what you personally worked on, any obstacles you faced, and how you resolved them. Show adaptability and ownership.

5. Summarize outcomes and learnings

Share the results (e.g., performance improvements, user impact) and what you learned about system design and teamwork.

Key Points to Mention

  • Specific technical trade-offs (e.g., consistency vs. availability, latency vs. cost)
  • Constraints that influenced design (e.g., scale, latency, budget, team size)
  • Alternatives considered and why they were rejected
  • Your individual contribution and how you handled ambiguity
  • Metrics or outcomes that demonstrate impact
  • Lessons learned about system design or collaboration

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q2

Solve a LeetCode Hard level coding problem.

Algorithms & Data Structures
Author's notes

Was not expecting Hard difficulty for a first round screen.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem constraints and edge cases, then discuss brute force and optimize using appropriate data structures and algorithms. Think aloud, write clean code, and test with examples to demonstrate problem-solving and communication skills.

Pro tip: At TikTok, interviewers value efficient, scalable solutions and clear communication. Always analyze time and space complexity and discuss potential optimizations, even if you don't implement them.

1. Understand the Problem

Ask clarifying questions to confirm input/output, constraints, and edge cases. Restate the problem in your own words to ensure alignment.

2. Explore Approaches

Discuss a brute-force solution first, then identify bottlenecks and propose optimized approaches using suitable data structures or algorithms.

3. Plan and Code

Outline your chosen approach step-by-step, then write clean, modular code while explaining your thought process.

4. Test and Debug

Walk through your code with sample inputs, including edge cases, and fix any issues. Verify correctness and efficiency.

5. Analyze and Optimize

State the time and space complexity of your solution and discuss potential improvements or trade-offs.

Key Points to Mention

  • Time and space complexity analysis
  • Edge cases and constraints handling
  • Choice of data structures and algorithms
  • Code readability and modularity
  • Testing methodology and debugging
  • Communication and thought process

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.