What the round looks like
You share your screen with your own assistant open. The brief is a paragraph: an order validator that checks, for instance, whether an order contains prohibited items or whether its price is within some range; rules can be added and removed; rules have dependencies between them, forming a directed acyclic graph. That is the whole spec. The follow-up arrives once the basics work: when a rule is removed, its prerequisites become the prerequisites of the rules that depended on it.
The candidate built it, got to the follow-up, and did not finish adding the test cases before time ran out. The rejection came the same day. Their own note for the next person was that it was their first AI-assisted coding interview.
What the thin brief is doing
Nothing in the prompt says what an order is, what a rule returns, what happens on a cycle, or whether a prerequisite may name a rule that does not exist yet. With an assistant at hand, that is the round: the code is cheap, the decisions are not, and the interviewer is watching which decisions you make, which you ask about, and whether the tests you write pin them down. The removal follow-up is the same move again. Rewiring the graph is a few lines once you have said what the rule is; saying what the rule is, including what happens to duplicates and to order, is the work.
Our read: budget the hour backwards from the tests. The reported candidate lost the round at the end, not at the start.
What is confirmed, and what is not
- Reported once, so treat as one data point: everything above. An AI-assisted first round with your own tool and a shared screen; the order validator with addable and removable rules and DAG dependencies; the removal-rewiring follow-up; tests expected within the time.
- Not known: whether other TikTok teams run the same format, how the round is scored, the language expected, and whether the prompt is the same for every candidate.
How we would prepare
- Write the order shape and the rule interface first. One line each, said aloud, before any prompt. The assistant builds on whatever you decide; decide it.
- Know what a dependency means for validation. A rule runs only after its prerequisites passed, a failed prerequisite skips its dependants, and the result says which. Have that rule ready and test it.
- Have an answer for cycles and unknown names. Refuse at add time, or at validation time, but choose, and make the assistant's code match the choice.
- Spend the last fifteen minutes on tests, not features.One per rule you decided, including the removal rewiring with a name already listed by the dependant.
Nyrion's TikTok section starts with Order Validator, built from this report. Rules with prohibited items and a price range, add and remove, then prerequisites forming a DAG with forward references, cycle refusal and skipped dependants, then the removal follow-up as its own stage with the rewiring rule spelled out. The task and the follow-up are what the candidate describes; the order shape, the rule interface, the result shape and the exact rewiring rule are ours.
How this round compares with other companies' versions, and what every version grades: the AI coding interview guide.
Frequently asked, briefly answered
Which TikTok round is AI-assisted?
The first-round coding interview for a software engineer on the e-commerce side (shipping and logistics), in the one report we have read, from August 2026. The candidate used their own AI tool with the screen shared.
What was the prompt?
Write an order validator. Rules such as whether an order contains prohibited items or whether its price is within a range; rules can be added and removed; rules have dependencies between them that form a directed acyclic graph. The follow-up: when a rule is removed, its prerequisites become the prerequisites of the rules that depended on it.
What went wrong for the candidate?
Time. They did not finish adding the test cases at the end and were rejected the same day. Tests were expected as part of the delivery, not as a bonus.
How much is specified?
Little. The signatures, the order schema, the error behaviour and the graph edge cases were all left to the candidate. Clarify before coding, and say your assumptions aloud; the follow-up about removal rewiring is a question about a rule you have to choose.
Which assistant?
Your own. The report says nothing about a provided one, and the screen share is how the interviewer sees how you use it.
Practice problems tagged for TikTok
Browse the catalog and open the TikTok section. No login required to look; sign in when you want to solve one.