Instacart uses CodeSignal at the top of its engineering hiring funnel. Instacart uses several role-specific coding screens in addition to the standard format. One senior engineering candidate in 2025 took the standard coding screen, while senior engineering and full-stack candidates in 2026 faced longer, multi-step implementation exercises in an existing codebase.

When to Expect the OA for Your Role

CodeSignal's Instacart customer story places certified assessments at the top of Instacart's hiring funnel. Recent candidates have received the screen before recruiter and onsite interviews.

One 2025 senior candidate received a standard CodeSignal OA. A separate 2026 senior candidate described a 90-minute, four-part key-value-store task followed by an AI-assisted Karat exercise. One 2026 full-stack process used five phases covering requirements, implementation, debugging, and a feature extension. Your invitation should make clear which track applies.

Does Your Online Assessment Matter?

Instacart uses the assessment to decide who advances early in the process. The company does not publish a universal cutoff. The traditional CodeSignal format rewards correct, well-implemented solutions that pass the tests. The newer format assesses requirements analysis, work in an unfamiliar codebase, debugging, and test strategy. Treat each phase as scored work. Submit stable progress in small changes and avoid leaving one large change unfinished.

Compiled List of Instacart OA Question Types

These problems cover arrays, strings, matrices, timestamped state, caches, parsing, aggregation, and nested data.

1. Time Based Key-Value Store — versioned lookup by timestamp
2. LRU Cache — bounded state and eviction
3. Spiral Matrix — matrix boundaries and traversal
4. Decode String — nested parsing with a stack
5. Evaluate Division — graph relationships and query evaluation
6. Flatten Nested List Iterator — lazy traversal of nested values
7. Top K Frequent Elements — aggregation and selection
8. Group Anagrams — string normalization and grouping
9. Merge Intervals — sorting and overlapping ranges
10. Design In-Memory File System — hierarchical state and API behavior

Instacart Interview Questions

Recently asked in real interviews

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

Encoded Matrix

coding Medium

A Hand of Three Cards

coding Hard

Average Travel Time

coding Easy

Timestamped Key-Value Store

coding Medium

Pattern Finding

coding Easy

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How to Prepare and Pass the Instacart Online Assessment

Prepare for both versions until the exact format is confirmed. For a standard screen, complete a 70- to 90-minute practice block covering arrays, strings, maps, matrices, and stateful designs. Solve the faster problems first, then use the remaining time for the hardest implementation and its edge cases.

For the project-style track, practice reading an unfamiliar repository, locating the code for a feature, understanding the requirements, implementing the feature, fixing a related bug, and running focused tests. Keep each change small enough to validate before the next step. Use Lodely to practice Instacart coding and system design questions before the live interview loop.

Instacart Interview Question Breakdown

Time Based Key-Value Store

Type: Stateful data structures. Prompt: Store multiple values for a key and return the value at or before a given time. The Trick: The query needs to handle timestamps that fall between recorded versions or before the first version. What It Tests: API design, ordered history, and edge cases.

Design In-Memory File System

Type: Object and hierarchy design. Prompt: Model directories, files, paths, and updates without external storage. The Trick: Path parsing and file and directory behavior must remain consistent across all methods. What It Tests: Maintaining invariants across a codebase with multiple operations.

What Comes After the Online Assessment

Recent processes have included recruiter contact, a coding interview, system design, and a behavioral interview. An AI-assisted Karat exercise is being introduced in the 2026 senior track in addition to the full interview loop. Carry the same habits into those interviews: clarify requirements before coding, write concise tests, and explain how your design handles extensions.

Conclusion

Match your preparation to the exact CodeSignal track and practice incremental, testable progress. Use Lodely to prepare for the Instacart coding and design interviews that follow.