INTERVIEW GUIDE

Palantir Software Engineer Interview: Questions & Process

Palantir's software engineer interview is best known for its 'decomposition' round — an open-ended, real-world problem you have to model, decompose into objects/components, and design on the spot. Around that sit a coding screen and standard coding/behavioral rounds. Raw algorithm speed matters less here than clear domain modeling, pragmatism, and how you reason about messy real systems.

The interview process

1. Recruiter screen — ~30 min call

Tests: background, interests, why Palantir, and how the process works

2. Coding screen — 60 min (HackerRank or live)

Tests: 1-2 algorithm/data-structure problems with working, correct code under time

3. Decomposition interview — 45-60 min design discussion

Tests: Palantir's signature round — take a vague real-world problem, model the domain into objects and interfaces, and decompose it into components you could build

4. Coding round (onsite) — 45-60 min live coding

Tests: implementing part of a system cleanly, handling edge cases, and writing code others could maintain

5. Behavioral / values — 45 min

Tests: ownership, working through ambiguity, collaboration, and motivation for Palantir's mission

Questions you're likely to get

Technical

Count the number of connected regions in a 2D grid (islands) and explain your traversal.
Merge a set of overlapping intervals into the minimum set of non-overlapping intervals.
Given meeting time intervals, find the minimum number of rooms required.
Group a list of strings into anagrams.
Design an LRU cache with O(1) operations — what backs it and why?
Implement a prefix tree (trie) supporting insert and prefix search.

Role-specific

Decomposition: model a ride-sharing system — what are the core objects, their relationships, and the key operations?
Decomposition: design the data model and components for an elevator control system in a tall building.
Decomposition: you're asked to build a tool to detect fraudulent transactions — how do you break the problem down?
How would you model a system where the requirements are still vague and likely to change?
Where would your design break at 100x scale, and what would you change first?

Behavioral

Tell me about a time you took an ambiguous problem and gave it structure.
Describe a project where the requirements changed midway — how did you adapt your design?
Why Palantir? What about the mission and the kind of problems matters to you?

Practice these problems live

Relevant LeetCode problems for the Palantir Software Engineer loop. Start a live, AI-run coding interview on any of them — or open the problem on LeetCode.

▶ Number of Islands· Medium · LeetCode #200

Number of Islands is a clean grid BFS/DFS — a common coding-screen problem and a gentle lead-in to spatial modeling.

▶ Merge Intervals· Medium · LeetCode #56

Merge Intervals tests the practical array/sorting reasoning Palantir favors over puzzle tricks.

▶ Meeting Rooms II· Medium · LeetCode #253

Meeting Rooms II layers a heap onto intervals — real-world scheduling logic that mirrors decomposition thinking.

▶ Group Anagrams· Medium · LeetCode #49

Group Anagrams checks hash-map design and clean data organization under time.

▶ LRU Cache· Medium · LeetCode #146

LRU Cache is a design problem (hash map + linked list) rewarding the readable, maintainable code Palantir cares about.

▶ Implement Trie (Prefix Tree)· Medium · LeetCode #208

Implement Trie tests building a small data structure from scratch, close to the 'design a component' style of the loop.

How to answer (worked examples)

Decomposition: model a ride-sharing system.

Don't start coding. Start by asking scoping questions, then name the core entities (Rider, Driver, Trip, Location, Matcher) and their relationships and key operations. Talk through the interfaces between components and how data flows — request → match → trip lifecycle → completion. Then stress-test your own model: what changes if drivers can cancel, or if you need surge pricing? Palantir is scoring clear object modeling and how gracefully your design absorbs new requirements.

Design an LRU cache with O(1) operations.

Lead with the data structures: a hash map for O(1) lookup plus a doubly linked list for recency ordering, with the map pointing at list nodes. Walk get and put, moving touched nodes to the head and evicting the tail. Volunteer edge cases (existing key update, zero capacity). Keep the code clean and readable — maintainability is an explicit signal here.

Tell me about a time you gave an ambiguous problem structure.

STAR, with the Action centered on how you decomposed the problem: the questions you asked to scope it, the model or plan you proposed, and how you validated it before building. End with the outcome and what you'd refine. This mirrors the decomposition round, so it doubles as a preview of how you think.

What Palantir looks for

Strong domain modeling — you turn a vague problem into clear objects, interfaces, and components
Pragmatism: designs that are buildable and adaptable, not maximally clever
Clean, readable, maintainable code with handled edge cases
Comfort with ambiguity — you scope and structure instead of waiting for a full spec
Genuine engagement with the problem and Palantir's mission
Red flag: jumping to implementation before modeling the domain, or a design that shatters when requirements shift

FAQ

What is the 'decomposition' interview really testing?

Your ability to take an open-ended real-world problem and break it into a clean object/component model with sensible interfaces — and to evolve that model as requirements change. It's design and modeling, not algorithm trivia.

Is Palantir as LeetCode-heavy as other big tech?

There's a real coding screen, but Palantir weights design, modeling, and pragmatism more than raw algorithm speed. Don't only grind puzzles — practice modeling systems out loud.

What language should I use?

Whatever you're strongest in. Palantir uses Java heavily internally, but for interviews they care about how you model and write code, not the specific stack.

How do I prep for the decomposition round?

Practice modeling everyday systems (parking garage, elevator, vending machine, ride-share) by naming entities, relationships, and operations, then deliberately add a new requirement and adapt. Narrate the whole time.

How long is the process?

Typically 3-5 weeks, though scheduling the onsite panel and decision can vary.

The decomposition round rewards thinking out loud

Palantir's signature interview is a conversation — model a messy problem, then defend and adapt your design live. Practice decomposition and the coding rounds out loud with OfferLoop's voice coach so you walk in fluent, not freezing.

Practice this interview out loud →

All Palantir interviews →Palantir Data Analyst interview →Palantir Data Scientist interview →Palantir Data Engineer interview →Palantir Machine Learning Engineer interview →

OfferLoop is an independent interview-practice tool and is not affiliated with, endorsed by, or sponsored by Palantir. All company names and trademarks are the property of their respective owners.

Interview formats vary by team, level and year, and this guide is compiled from general knowledge of publicly discussed hiring processes — treat it as preparation material, not an official description of Palantir's current process.