PayPal Backend Engineer Interview Questions
The questions to prepare for a PayPal Backend Engineer interview. Questions from real interview reports rank first. Updated daily.
Use 3D dynamic programming to maximize rewards collected by two PayPal checkout agents moving through a grid.
PayPalNormalize a string, detect palindromes, find the longest palindromic substring, and compute minimum insertions using two pointers and dynamic programming.
PayPalDesign a real-time fraud scoring system for card transactions with strict latency, delayed labels, and high availability requirements.
PayPalDesign Venmo's payment and request flow with ledger correctness, real-time ML risk scoring, and safe degradation.
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Explain how data structures and operating-system concepts solved a backend problem, including trade-offs, verification, and failure handling.
PayPalTests data modeling skills, normalization, indexing, and performance considerations for production systems.
PayPalTests your hands-on containerization knowledge and how you apply it in deployment workflows.
PayPalTests your ability to diagnose and improve SQL performance using query and indexing strategies.
PayPalUse LAG to identify PayPal transactions matching a prior record within five minutes.
PayPalCalculate PayPal Checkout conversion rates by acquisition channel and device using a CTE, LEFT JOIN, and conditional aggregation.
PayPalUse aggregation and ranking to find the top three PayPal transaction categories for one merchant during a quarter.
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