Pinterest Interview Questions
Practice 125 real Pinterest interview questions for 2026. Covers all top categories — Coding & Algorithms, Data Manipulation (SQL/Python), Analytics & Experimentation, Machine Learning, System Design — across Data Scientist, Software Engineer, Machine Learning Engineer, and Data Analyst roles. Real questions from actual interviews with detailed solutions. This collection leans hard on coding and algorithm problems for SWE candidates while giving equivalent weight to experiment design, SQL/Python analytics, and model evaluation for data roles, making it a focused resource for interview preparation for screens, virtual onsites, and take-home assignments. Expect interviews to evaluate algorithmic thinking, production design, experimental rigor, and clear data storytelling. For Data Scientists you’ll see carousel and billboard lift evaluation, weighted/random-sampling implementations, numpy/pandas and SQL analytics on category and video-time metrics, and survey-balance diagnostics. Software Engineers face prefix-matching, catalog update pipelines, sparse-matrix ops, grid/graph puzzles, and ads event reporting or blob storage design. Machine Learning Engineers get pin-search and recommender design, Naive Bayes/bagging implementation, hyperparameter generation, and sampling-by-score problems. Data Analysts encounter cohort and cancellation/rebooking metric questions. Prepare with timed coding drills, end-to-end A/B case studies, polished Python/SQL practice, and concise STAR stories for behavioral rounds.

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"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."

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"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."

"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."

"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."

"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Design a Distributed Rate Limiter
Design a distributed rate limiting service for a public API platform. The service sits on the request path of every API gateway and application server...
Write SQL for top categories and highly active users
You are given three tables: 1) impression Event-level table of user impressions. - impression_id BIGINT (PK) - user_id BIGINT (FK → user.user_id) - pi...
How would you evaluate a carousel launch?
You are the data scientist supporting Pinterest's home feed. Product wants to add a horizontally scrollable carousel at the top of the app, similar to...
Maximize Boxes Stored Through One Entrance
You are given two integer arrays: - boxes[i]: the height of the i-th box. - rooms[j]: the height limit of the j-th room in a linear warehouse. The war...
Implement a Sparse Matrix Class
Implement a SparseMatrix class for matrices that contain mostly zero values. Your class should support the following operations: 1. Construction and s...
Solve Expression and Tree-List Problems
The coding portion included two algorithm problems: 1. Generate expressions with left-to-right evaluation Given a string num containing only di...
Explain bias–variance, overfitting, and vanishing gradients
Answer the following ML fundamentals questions: 1. Bias–variance tradeoff: What are bias and variance? How do they relate to underfitting/overfitting?...
Evaluate Fresh Content and Video Experiments
Pinterest wants to improve the perceived freshness and engagement of the home feed. Answer the following interview questions: 1. Define a practical me...
Design Catalog Update Pipeline
Design a system that takes a very large product catalog, for example 500 million records, and propagates updates to all downstream internal systems. E...
Hierarchical Access Control for an Advertising Platform
Design an access-control system for an advertising platform. Advertisers are organized into a hierarchy of groups. A group may contain other groups (s...
First Word Matching Each Prefix Query
You are given a list of words (the dictionary) and a list of queries, where each query is a string prefix. For each query, return the index (0-based, ...
Reconstruct route from unordered travel tickets
You are given a list of directed travel tickets, each represented as a pair [from, to] (city names are strings), e.g. [["A","B"],["B","C"], ...]. The ...
Insert parentheses to minimize expression value
You are given a string expression of the form A+B, where A and B are non-empty strings of digits (no digit is '0'). You must insert exactly one pair o...
Generate all hyperparameter combinations
You are given several groups of hyperparameter choices for an ML experiment. Each group contains one hyperparameter name and a list of candidate value...
Solve Multiple Coding Interview Problems
The interview included the following independent coding tasks. Solve each task, explain edge cases, and analyze time and space complexity. 1. Minimum ...
Design a violation log analyzer
You are given an append-only list of violation events as tuples (id: string, policy: string, date: ISO-8601 string). Build an in-memory "Violation Log...
Find top category by video time spent
Pandas required. You are given a DataFrame df with columns: user_id (int), pin_id (int), pin_type (str), category (str or None), time_spent_sec (numer...
Implement Naive Bayes classifier from scratch
Implement a Naive Bayes classifier from scratch (you may use NumPy). Write a class with: - fit(X, y): estimate class priors and feature likelihood par...
Design an ads event reporting system
Design an ads event reporting system that collects user-ad interaction events and serves aggregated metrics. Requirements 1. Ingest events from multip...
Evaluate Carousel and Billboard Lift
You are the product data scientist supporting Pinterest. Two analytics prompts were described: 1. Carousel feature at the top of the home feed. Pinter...