Paypal Interview Questions
Master your tech interview with our curated database of real questions from top companies.
Identify Unsupervised Techniques for Detecting Fraudulent Transactions
Unsupervised Fraud Detection: Modeling and Evaluation Without Labels Scenario You receive millions of historical transactions with no fraud labels. Ma...
Clean and Analyze User Transactions with Python Functions
transactions +---------+---------------------+---------+ | user_id | trans_ts | amount | +---------+---------------------+---------+ | 11 ...
Master A/B Testing: Key Concepts and Methodologies Explained
A/B Testing and Causal Inference: Core Concepts and Practice Scenario You are a data scientist interviewing for a role working on an online product. Y...
Identify Users with Specific Page Visit Sequence
page_visits +------------+---------+---------+----------+ | date | user_id | page_id | ts | +------------+---------+---------+----------+ ...
Analyze Transactions for Risk and Implement Mitigation Strategies
Real-Time Payments Risk: Accept or Decline, With Immediate Mitigations Scenario Two new card transactions arrive, and you must decide in real time whe...
Identify Session with Maximum Overlapping Sessions Count
sessions | session_id | start_time | end_time | | 1 | 2023-01-01 09:00:00 | 2023-01-01 10:00:00 | | 2 | 2023-0...
Analyze Transactions and Classify by Amount in SQL
transactions +---------------+---------+--------+---------+---------------------+-----------------+ | transaction_id| user_id | amount | status | ts ...
Describe Leading Without Authority in Data Management
Behavioral & Leadership Interview — Data Scientist (Onsite) Context You will be assessed on cultural fit and how you operate in ambiguous, messy data ...
Discuss Project Motivation and Career Goals
Behavioral Phone Screen Prompts — Software Engineer (PayPal) Context: You are in a technical phone screen for a Software Engineer role. Expect concise...
Implement sliding-window device anomaly
Streaming detection algorithm: Implement a function process_logins(stream) that consumes a time-ordered stream of login events (user_id, ts, device_id...
Influence policy with BI deliverables
BI/Fraud Stakeholder Case: Drive an Account Takeover (ATO) Policy Change in 90 Days You join the Chicago Fraud team as a Decision Scientist. The hirin...
Build a real-time ATO model
End-to-end ML Case: Real-time Detection of Venmo Account Takeover (ATO) at Authorization Context Design a real-time machine learning system that score...
Optimize thresholds under fraud costs
Cost-sensitive Thresholding for Fraud (ATO) Classifier Context You are evaluating a binary classifier for account takeover (ATO) fraud on a large vali...
Design an A/B for ATO rule
Experiment Design Case: Real-time ATO Rule for PayPal/Venmo Context: You are designing and analyzing an online experiment to estimate the net business...
Write SQL to flag Venmo ATO
SQL case: You are a Decision Scientist on Venmo’s Fraud (ATO) team. Using the schema and sample data below, write a single Standard SQL query that ret...
Design a traditional fraud detection system
Design an End-to-End Real-Time Payments Fraud Detection System Context: You are designing a fraud detection system for a large-scale online payments p...
Assess LLMs for fraud detection
LLMs in Fraud Detection: Near-Term vs. Long-Term Roles Context You are designing fraud detection for a large-scale digital payments platform with: - R...
Search a word in a grid
Given a 2D grid of characters and a target word, determine if the word can be traced by moving up, down, left, or right, using each cell at most once....
Maximize ones with limited flips
Given a binary array and an integer k, return the length of the longest contiguous subarray achievable by flipping at most k zeros to ones. Explain an...
Design RL-based spending limit policy
RL System Design: Per‑User Spending Limits You are designing a reinforcement learning (RL) system to set per-user spending limits in a payments/risk c...