Pinterest Machine Learning Engineer Interview Questions

Practice the exact questions companies are asking right now.

34 Questions 1 Company07.03.2026
Showing 20 results
Role
Pinterest logo
Pinterest
Hard
Machine Learning Engineer

Prevent Vanishing Gradients in Deep Networks

Prevent Vanishing Gradients in Deep Networks Clarifying Questions to Ask - Are we discussing feed-forward networks, recurrent networks, or both? - Sho...

Machine Learning
11
0
88 people solved
Jul 3, 2026
Pinterest logo
Pinterest
Medium
Machine Learning Engineer

Design User and Item Embeddings from Long Histories

Design User and Item Embeddings from Long Histories Design an embedding system that represents users and visual-content items for retrieval or recomme...

ML System Design
8
0
96 people solved
Jul 2, 2026
Pinterest logo
Pinterest
Medium
Machine Learning Engineer

Rank Newly Launched Ads Under Cold Start

Rank Newly Launched Ads Under Cold Start Design a ranking model dedicated to ads launched within the last seven days, where direct performance history...

ML System Design
10
0
73 people solved
Jul 2, 2026
Pinterest logo
Pinterest
Medium
Machine Learning Engineer

Describe a Failure or Mistake and Its Lasting Lesson

Describe a Failure or Mistake and Its Lasting Lesson Tell me about a meaningful professional failure or mistake. What did you own, how did you respond...

Behavioral & Leadership
3
0
43 people solved
Jul 2, 2026
Pinterest logo
Pinterest
Hard
Machine Learning Engineer

Explain a Project Through Business Impact and User Value

Explain a Project Through Business Impact and User Value Prompt Describe a project from your current or recent work. Explain the problem, your contrib...

Behavioral & Leadership
3
0
35 people solved
Jul 3, 2026
Pinterest logo
Pinterest
Hard
Machine Learning Engineer Locked

Bias-Variance Tradeoff and Vanishing Gradients in Feedforward Networks

This question evaluates conceptual understanding of the bias-variance tradeoff and the vanishing-gradient problem in deep feedforward networks, two co...

Machine Learning
8
0
112 people solved
Jun 12, 2026
Pinterest logo
Pinterest
Hard
Machine Learning Engineer

Implement a Stateful Search Autocomplete Session

Implement a Stateful Search Autocomplete Session Build an autocomplete engine from historical sentences and their usage counts. While a user types a s...

Coding & Algorithms
2
0
34 people solved
Jul 3, 2026
Pinterest logo
Pinterest
Hard
Machine Learning Engineer Locked

Explain overfitting, underfitting, and regularization

This question evaluates understanding of model generalization, overfitting versus underfitting, the bias–variance tradeoff, and regularization techniq...

Machine Learning
19
0
131 people solved
Mar 1, 2026
Pinterest logo
Pinterest
Medium
Machine Learning Engineer Locked

Design notification and feed recommenders

This question evaluates an engineer's ability to design scalable, production-ready recommendation systems for notifications and home feeds, encompassi...

ML System Design
13
0
125 people solved
Mar 8, 2026
Pinterest logo
Pinterest
Hard
Machine Learning EngineerSenior+ Locked

Design a real-time home feed ranker

This question evaluates an engineer's ability to design scalable, low-latency real-time recommendation and ranking systems that integrate personalizat...

ML System Design
15
0
119 people solved
Jan 12, 2026
Pinterest logo
Pinterest
Medium
Machine Learning Engineer Locked

First Word Matching Each Prefix Query

This question evaluates a candidate's grasp of string data structures and efficient prefix-matching techniques, core competencies in coding and algori...

Coding & Algorithms
1
0
13 people solved
Jun 3, 2026
Pinterest logo
Pinterest
Hard
Machine Learning Engineer

Implement bagging with decision trees

Implement a simple bagging (bootstrap aggregating) classifier that uses decision trees as base learners. You are given a template with a DecisionTree ...

Machine Learning
10
0
115 people solved
Feb 9, 2026
Pinterest logo
Pinterest
Hard
Machine Learning Engineer

Solve a 9x9 Sudoku puzzle

Given a partially filled 9×9 Sudoku board, fill the empty cells so that the completed board is valid. A valid Sudoku satisfies: - Each row contains di...

Coding & Algorithms
18
1
139 people solved
Dec 13, 2025
Pinterest logo
Pinterest
Medium
Machine Learning EngineerSenior+ Locked

Design Detection Systems for Risk and Safety

This question evaluates a machine learning engineer's competence in designing end-to-end detection systems for risk and safety, covering skills in dat...

ML System Design
7
0
72 people solved
Feb 21, 2026
Pinterest logo
Pinterest
Hard
Machine Learning Engineer

Answer core ML fundamentals questions

You are asked several short ML fundamentals questions: 1) Define precision and recall for a binary classifier and explain how they relate to a confusi...

Machine Learning
15
0
142 people solved
Feb 9, 2026
Pinterest logo
Pinterest
Hard
Machine Learning Engineer

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...

Machine Learning
6
0
98 people solved
Feb 9, 2026
Pinterest logo
Pinterest
Medium
Machine Learning Engineer Locked

Explain bias–variance, overfitting, and vanishing gradients

This question evaluates understanding of core machine learning fundamentals—specifically the bias–variance tradeoff, overfitting detection and mitigat...

Machine Learning
11
0
162 people solved
Jan 22, 2026
Pinterest logo
Pinterest
Easy
Machine Learning Engineer

Explain learning-rate fluctuation and vanishing gradients

ML Fundamentals Answer the following conceptual questions: 1. Learning rate vs. training stability: Why can training metrics (loss/accuracy) fluctuate...

Machine Learning
10
0
107 people solved
Dec 15, 2025
Pinterest logo
Pinterest
Hard
Machine Learning Engineer

Design an ads system to improve CTR

Design an ML system to increase the click-through rate (CTR) of ads shown in the personalized feed of an online social media platform. You run the ran...

ML System Design
17
0
149 people solved
Dec 13, 2025
Pinterest logo
Pinterest
Hard
Machine Learning EngineerSenior+ Locked

Design an unsafe content detection system

This question evaluates a candidate's competency in end-to-end machine learning system design for unsafe user-generated content detection, covering mu...

ML System Design
12
0
120 people solved
Jan 12, 2026

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