The Trade Desk often uses CodeSignal for software-engineering screens. One recent account described a 90-minute, four-level implementation project in which each level unlocked sequentially. A separate account described four general coding questions under a shorter time limit.

When to Expect the OA for Your Role

Candidates for new-graduate, internship, or full-time software roles typically receive the assessment after application review or an initial recruiter interaction. One recent applicant described a 90-minute, multi-level banking-system task. A separate account of an early-career process described a four-problem CodeSignal screen. A senior hire may receive a take-home exercise or move directly to live design and coding interviews.

Does Your Online Assessment Matter?

The screen helps determine who advances. Partial progress can still earn platform credit. In the layered format, later requirements must remain compatible with code from earlier levels. The Trade Desk doesn't publish a general cutoff. Preserve existing behavior as each level adds new requirements.

Compiled List of The Trade Desk OA Question Types

Useful practice areas include stateful systems, parsing, caches, arrays, graphs, and dynamic programming.

1. LeetCode - Simple Bank System — validating and processing stateful transactions.
2. LRU Cache - constant-time access and cache eviction.
3. Basic Calculator - parsing expressions and nested states.
4. Trapping Rain Water — two-pointer boundary method.
5. Word Ladder - shortest paths in a graph with implicit neighbors.
6. Number of Islands - connected components in a grid.
7. Longest Common Prefix — string comparison and boundary control.
8. Best Time to Buy and Sell Stock IV — DP with transaction state.

The Trade Desk Interview Questions

Recently asked in real interviews

These questions were asked recently in real The Trade Desk interviews. Practice these and 4,000+ other questions from 1,000+ companies on Lodely.

JSON Validator

coding Hard

Basic Calculator I, II, III (Triple Question)

coding Hard

Activity Benchmark Distance

coding Medium

Longest Subarray with Frequency Threshold

coding Medium

Design a custom policy extension for an LRU Cache.

system-design Medium

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How to Prepare and Pass the The Trade Desk Online Assessment

Spend one week on stateful class design, maps, caches, parsing, and graph traversal. Complete two 90-minute mocks in which you receive a small API and incremental requirements. Isolate operations, write a test after each stage, and confirm that existing code still works before adding ranking, scheduling, or merging. For a general coding screen, triage all questions in the first five minutes. Then use Lodely to practice The Trade Desk coding and system design questions.

The Trade Desk Interview Question Breakdown

Design a Bank

Type: Stateful object. Prompt: Support account creation and money operations with validation. The Trick: Define failure behavior and perform state updates atomically. What It Tests: Translating requirements and designing maintainable extension points.

LRU Cache

Type: Data-structure design. Prompt: Support key access within a fixed capacity and evict the least recently used entry. The Trick: Maintain eviction order alongside key lookup without linear scans. What It Tests: Maintaining invariants and analyzing complexity.

What Comes After the Online Assessment

Candidates who reach the final hiring stages usually complete a recruiter conversation, a live coding interview, and either a system design or object-oriented design interview. Later stages usually require candidates to explain how they break down ambiguous requirements and safely extend a solution. When coding, explain your assumptions before changing state or choosing a data structure. Review your OA architecture, trade-offs, and tests because the same reasoning applies in later interviews.

Conclusion

Implement code incrementally and keep it correct as requirements evolve. Use Lodely to continue practicing The Trade Desk coding, design, and behavioral questions.