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16+ Barclays questions

Barclays interview questions and how to prepare

The questions candidates report from Barclays interviews, sorted by how often they come up, with difficulty and topics, plus original practice written in Barclays's interview style.

Practice Barclays questions free All companies

ZorixOS tracks 16 community-reported Barclays interview questions, drawn from an open-source dataset of real interview reports and sorted by how frequently each one comes up. Every question links to its source. Alongside them are 78 original ZorixOS practice questions written in Barclays's known interview style (not claimed as asked at Barclays), so you can rehearse the real format. Practice any of them out loud in a free AI mock interview tuned to Barclays.

Updated July 2026

Barclays interview questions candidates report

Community-reported from real Barclays interviews (open-source dataset), most-asked first. Showing 16. Each links to its source.

  1. Lexicographically Smallest Generated String
    StringGreedyString Matching
    Hard100% asked
  2. Partition Labels
    Hash TableTwo PointersStringGreedy
    Medium100% asked
  3. Remove Boxes
    ArrayDynamic ProgrammingMemoization
    Hard100% asked
  4. Double Modular Exponentiation
    ArrayMathSimulation
    Medium90% asked
  5. Furthest Point From Origin
    StringCounting
    Easy90% asked
  6. Count Submatrices with Top-Left Element and Sum Less Than k
    ArrayMatrixPrefix Sum
    Medium88% asked
  7. Mark Elements on Array by Performing Queries
    ArrayHash TableSortingHeap (Priority Queue)
    Medium88% asked
  8. Lexicographical Numbers
    Depth-First SearchTrie
    Medium56% asked
  9. Longest Common Prefix
    ArrayStringTrie
    Easy56% asked
  10. Minimum Number of Days to Make m Bouquets
    ArrayBinary Search
    Medium56% asked
  11. Next Greater Element I
    ArrayHash TableStackMonotonic Stack
    Easy56% asked
  12. Number of Islands
    ArrayDepth-First SearchBreadth-First SearchUnion-Find
    Medium56% asked
  13. Reverse Words in a String
    Two PointersString
    Medium56% asked
  14. Second Highest Salary
    Database
    Medium56% asked
  15. Two Sum
    ArrayHash Table
    Easy53% asked
  16. Valid Parentheses
    StringStack
    Easy53% asked

Practice questions in Barclays's style

Original ZorixOS questions written the way Barclays interviews, so you rehearse the real format. Not claimed as asked at Barclays.

  1. Imagine Barclays is developing a new peer-to-peer payments feature within its mobile app to compete with Zelle or Venmo. Describe the high-level system architecture, focusing on data flow, security considerations, and scalability for millions of concurrent transactions. What are the key APIs you'd need?

    Software EngineerSystem DesignTests: Evaluates system design thinking, understanding of distributed systems, security principles, and API design in a financial context.

  2. A Barclays retail banking customer reports that their online banking transaction history is showing incorrect balances for the past 24 hours. How would you approach debugging this issue, starting from the customer's report to identifying the root cause in the backend systems?

    Software EngineerDebuggingTests: Assesses problem-solving skills, debugging methodology, and understanding of banking transaction systems.

  3. Barclays is considering integrating a new AI-powered chatbot for customer service to handle common queries about account management and transaction disputes. Discuss the technical challenges and trade-offs involved in building and deploying such a system, considering latency, accuracy, and integration with existing banking APIs.

    Software EngineerSystem DesignTests: Tests architectural decision-making, awareness of AI/ML system integration complexities, and non-functional requirements in a regulated environment.

  4. You're tasked with building a real-time fraud detection system for Barclays' credit card transactions. Outline the data pipelines, the types of features you'd consider, and the machine learning models you might employ. How would you handle concept drift in fraud patterns?

    Software EngineerCoding Reasoning / ML SystemsTests: Examines coding skills, understanding of data processing, ML model selection, and awareness of operational ML challenges.

  5. Barclays wants to offer a personalized financial advice service to its premium customers through its wealth management platform. Design the backend services required to store customer financial data securely, process it for insights, and present it through an API for the front-end.

    Software EngineerSystem DesignTests: Evaluates ability to design scalable and secure backend systems for sensitive financial data and personalized services.

  6. A common user complaint for Barclays' mobile banking app is slow loading times for transaction details after a recent update. Write a Python function to simulate retrieving transaction data and identify potential performance bottlenecks. Discuss optimizations.

    Software EngineerCoding Reasoning / PerformanceTests: Tests coding proficiency, performance optimization awareness, and ability to reason about code efficiency.

72+ more Barclays-style questions are in the free library, each practiceable live with adaptive follow-ups and an honest scorecard. Start free.

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Barclays Interview Questions (2026) | ZorixOS